Code
P1151
BMW
P — Powertrain
O2 Sensor Heater Circuit Signal Intermittent Bank 2 Sensor 1
Views:
UK: 17
EN: 42
RU: 31
AI status
Completed
Completed
100%
Causes
- Open or intermittent wiring/connector between the sensor and DME
- Corroded or loose sensor connector or pin(s)
- Failed oxygen sensor heater element
- Blown fuse or faulty relay supplying heater circuit
- High circuit resistance from damaged wiring, poor ground, or contamination
- Intermittent or failed DME (heater driver) output
Symptoms
- Check Engine MIL illuminated (fault stored)
- Failure to reach O2 sensor operating temperature quickly — cold‑response emissions problems
- Evaporative/OBD readiness monitors fail or set ‘not ready’ for heated O2 sensor
- Possible increased tailpipe emissions or rough running during cold start
- Intermittent or sporadic diagnostic faults rather than constant code
What to check
- Read freeze frame and live data; confirm Bank 2 Sensor 1 heater status and if code is intermittent or current
- Visually inspect sensor connector and wiring for corrosion, damage, heat chafe, rodent damage or water intrusion
- Wiggle test harness and connector with scan tool connected to reproduce the fault
- Measure heater resistance at the sensor (engine cold) and compare to specification
- Backprobe connector with key ON and measure supply voltage to heater and control signal from DME
- Check related fuses/relays and vehicle grounds
Signal parameters
- Battery supply voltage to heater circuit: ~11–14.5 V with key ON/engine running
- Typical heater element resistance (zirconia narrowband upstream sensor): approximately 2–10 ohms at ambient — consult BMW spec for exact value
- Heater current draw typically around 0.5–3 A (varies by sensor type)
- Control method: DME may switch ground or supply (PWM or on/off); expect switching frequency or on/off states depending on engine temp
- Intermittent condition: signal may drop to 0 V or open circuit intermittently or show erratic PWM
Diagnostic algorithm
- Connect a full‑function scan tool. Confirm P1151 is present and note freeze frame and pending/history status. Check live heater status for Bank 2 Sensor 1 while cranking and during warm‑up.
- Perform a visual inspection of the sensor, connector and harness from the sensor back to the engine wiring junction. Look for corrosion, melted insulation, chafe points near exhaust, or pin damage.
- With ignition OFF, disconnect the sensor and measure heater resistance across the heater pins at the sensor. Compare to BMW spec. An open or infinite resistance indicates failed heater.
- With ignition ON (engine OFF), backprobe the connector and verify battery voltage is present at the supply terminal and a control return is present (ground switching or PWM) from the DME. If no supply, check fuses/relays and upstream wiring.
- With engine cold and then during warmup, monitor the control signal with a scope or multimeter set to view switching. Look for intermittent loss of supply or control switching. Wiggle the harness at suspect areas to reproduce the fault.
- Check continuity and resistance between the sensor connector and the DME pin to rule out high resistance or intermittent open. Inspect and test all relevant grounds.
- If wiring and connectors are good but the DME output is intermittent or stuck, verify with an independent power source and consult manufacturer procedures — avoid replacing DME as first step. Consider replacing sensor with OEM‑spec unit and retest if heater element out of spec.
- Repair any damaged wiring, replace corrupted connectors, replace the oxygen sensor if heater is failed, clear codes and perform drive cycle to verify the fault does not return and monitors complete.
- If fault returns after correct wiring and sensor replacement, test/replace DME driver per factory diagnostics.
Likely causes
- Corroded/loose connector or damaged wiring at Bank 2 Sensor 1 (most common)
- Failed heater element inside the sensor
- Intermittent open/short in harness from heat/chafing near exhaust
- Blown fuse or poor ground for heater circuit
- Faulty DME heater driver (less common)
Fault status
Status
P1151 — O2 Sensor Heater Circuit Signal Intermittent: Bank 2 Sensor 1. Intermittent heater circuit fault detected; check wiring, connector, fuse/relay and sensor heater element.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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Code
P1151
DAEWOO
P — Powertrain
ACCEL POS SNSR CT MAL - ECU
Views:
UK: 2
EN: 6
RU: 10
AI status
Completed
Completed
100%
Causes
- Open or intermittent wiring/connector between the sensor and DME
- Corroded or loose sensor connector or pin(s)
- Failed oxygen sensor heater element
- Blown fuse or faulty relay supplying heater circuit
- High circuit resistance from damaged wiring, poor ground, or contamination
- Intermittent or failed DME (heater driver) output
Symptoms
- Check Engine MIL illuminated (fault stored)
- Failure to reach O2 sensor operating temperature quickly — cold‑response emissions problems
- Evaporative/OBD readiness monitors fail or set ‘not ready’ for heated O2 sensor
- Possible increased tailpipe emissions or rough running during cold start
- Intermittent or sporadic diagnostic faults rather than constant code
What to check
- Read freeze frame and live data; confirm Bank 2 Sensor 1 heater status and if code is intermittent or current
- Visually inspect sensor connector and wiring for corrosion, damage, heat chafe, rodent damage or water intrusion
- Wiggle test harness and connector with scan tool connected to reproduce the fault
- Measure heater resistance at the sensor (engine cold) and compare to specification
- Backprobe connector with key ON and measure supply voltage to heater and control signal from DME
- Check related fuses/relays and vehicle grounds
Signal parameters
- Battery supply voltage to heater circuit: ~11–14.5 V with key ON/engine running
- Typical heater element resistance (zirconia narrowband upstream sensor): approximately 2–10 ohms at ambient — consult BMW spec for exact value
- Heater current draw typically around 0.5–3 A (varies by sensor type)
- Control method: DME may switch ground or supply (PWM or on/off); expect switching frequency or on/off states depending on engine temp
- Intermittent condition: signal may drop to 0 V or open circuit intermittently or show erratic PWM
Diagnostic algorithm
- Connect a full‑function scan tool. Confirm P1151 is present and note freeze frame and pending/history status. Check live heater status for Bank 2 Sensor 1 while cranking and during warm‑up.
- Perform a visual inspection of the sensor, connector and harness from the sensor back to the engine wiring junction. Look for corrosion, melted insulation, chafe points near exhaust, or pin damage.
- With ignition OFF, disconnect the sensor and measure heater resistance across the heater pins at the sensor. Compare to BMW spec. An open or infinite resistance indicates failed heater.
- With ignition ON (engine OFF), backprobe the connector and verify battery voltage is present at the supply terminal and a control return is present (ground switching or PWM) from the DME. If no supply, check fuses/relays and upstream wiring.
- With engine cold and then during warmup, monitor the control signal with a scope or multimeter set to view switching. Look for intermittent loss of supply or control switching. Wiggle the harness at suspect areas to reproduce the fault.
- Check continuity and resistance between the sensor connector and the DME pin to rule out high resistance or intermittent open. Inspect and test all relevant grounds.
- If wiring and connectors are good but the DME output is intermittent or stuck, verify with an independent power source and consult manufacturer procedures — avoid replacing DME as first step. Consider replacing sensor with OEM‑spec unit and retest if heater element out of spec.
- Repair any damaged wiring, replace corrupted connectors, replace the oxygen sensor if heater is failed, clear codes and perform drive cycle to verify the fault does not return and monitors complete.
- If fault returns after correct wiring and sensor replacement, test/replace DME driver per factory diagnostics.
Likely causes
- Corroded/loose connector or damaged wiring at Bank 2 Sensor 1 (most common)
- Failed heater element inside the sensor
- Intermittent open/short in harness from heat/chafing near exhaust
- Blown fuse or poor ground for heater circuit
- Faulty DME heater driver (less common)
Fault status
Status
P1151 — O2 Sensor Heater Circuit Signal Intermittent: Bank 2 Sensor 1. Intermittent heater circuit fault detected; check wiring, connector, fuse/relay and sensor heater element.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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Code
P1151
FORD
P — Powertrain
Lack of Upstream Heated Oxygen Sensor Switch Sensor Indicates Lean Bank 2
Views:
UK: 23
EN: 53
RU: 37
AI status
Completed
Completed
100%
Causes
- Open or intermittent wiring/connector between the sensor and DME
- Corroded or loose sensor connector or pin(s)
- Failed oxygen sensor heater element
- Blown fuse or faulty relay supplying heater circuit
- High circuit resistance from damaged wiring, poor ground, or contamination
- Intermittent or failed DME (heater driver) output
Symptoms
- Check Engine MIL illuminated (fault stored)
- Failure to reach O2 sensor operating temperature quickly — cold‑response emissions problems
- Evaporative/OBD readiness monitors fail or set ‘not ready’ for heated O2 sensor
- Possible increased tailpipe emissions or rough running during cold start
- Intermittent or sporadic diagnostic faults rather than constant code
What to check
- Read freeze frame and live data; confirm Bank 2 Sensor 1 heater status and if code is intermittent or current
- Visually inspect sensor connector and wiring for corrosion, damage, heat chafe, rodent damage or water intrusion
- Wiggle test harness and connector with scan tool connected to reproduce the fault
- Measure heater resistance at the sensor (engine cold) and compare to specification
- Backprobe connector with key ON and measure supply voltage to heater and control signal from DME
- Check related fuses/relays and vehicle grounds
Signal parameters
- Battery supply voltage to heater circuit: ~11–14.5 V with key ON/engine running
- Typical heater element resistance (zirconia narrowband upstream sensor): approximately 2–10 ohms at ambient — consult BMW spec for exact value
- Heater current draw typically around 0.5–3 A (varies by sensor type)
- Control method: DME may switch ground or supply (PWM or on/off); expect switching frequency or on/off states depending on engine temp
- Intermittent condition: signal may drop to 0 V or open circuit intermittently or show erratic PWM
Diagnostic algorithm
- Connect a full‑function scan tool. Confirm P1151 is present and note freeze frame and pending/history status. Check live heater status for Bank 2 Sensor 1 while cranking and during warm‑up.
- Perform a visual inspection of the sensor, connector and harness from the sensor back to the engine wiring junction. Look for corrosion, melted insulation, chafe points near exhaust, or pin damage.
- With ignition OFF, disconnect the sensor and measure heater resistance across the heater pins at the sensor. Compare to BMW spec. An open or infinite resistance indicates failed heater.
- With ignition ON (engine OFF), backprobe the connector and verify battery voltage is present at the supply terminal and a control return is present (ground switching or PWM) from the DME. If no supply, check fuses/relays and upstream wiring.
- With engine cold and then during warmup, monitor the control signal with a scope or multimeter set to view switching. Look for intermittent loss of supply or control switching. Wiggle the harness at suspect areas to reproduce the fault.
- Check continuity and resistance between the sensor connector and the DME pin to rule out high resistance or intermittent open. Inspect and test all relevant grounds.
- If wiring and connectors are good but the DME output is intermittent or stuck, verify with an independent power source and consult manufacturer procedures — avoid replacing DME as first step. Consider replacing sensor with OEM‑spec unit and retest if heater element out of spec.
- Repair any damaged wiring, replace corrupted connectors, replace the oxygen sensor if heater is failed, clear codes and perform drive cycle to verify the fault does not return and monitors complete.
- If fault returns after correct wiring and sensor replacement, test/replace DME driver per factory diagnostics.
Likely causes
- Corroded/loose connector or damaged wiring at Bank 2 Sensor 1 (most common)
- Failed heater element inside the sensor
- Intermittent open/short in harness from heat/chafing near exhaust
- Blown fuse or poor ground for heater circuit
- Faulty DME heater driver (less common)
Fault status
Status
P1151 — O2 Sensor Heater Circuit Signal Intermittent: Bank 2 Sensor 1. Intermittent heater circuit fault detected; check wiring, connector, fuse/relay and sensor heater element.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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Code
P1151
Generic
P — Powertrain
Lack Of HO2S21 Switch - Sensor Indicates Lean
Views:
UK: 21
EN: 65
RU: 35
AI status
Completed
Completed
100%
Causes
- Open or intermittent wiring/connector between the sensor and DME
- Corroded or loose sensor connector or pin(s)
- Failed oxygen sensor heater element
- Blown fuse or faulty relay supplying heater circuit
- High circuit resistance from damaged wiring, poor ground, or contamination
- Intermittent or failed DME (heater driver) output
Symptoms
- Check Engine MIL illuminated (fault stored)
- Failure to reach O2 sensor operating temperature quickly — cold‑response emissions problems
- Evaporative/OBD readiness monitors fail or set ‘not ready’ for heated O2 sensor
- Possible increased tailpipe emissions or rough running during cold start
- Intermittent or sporadic diagnostic faults rather than constant code
What to check
- Read freeze frame and live data; confirm Bank 2 Sensor 1 heater status and if code is intermittent or current
- Visually inspect sensor connector and wiring for corrosion, damage, heat chafe, rodent damage or water intrusion
- Wiggle test harness and connector with scan tool connected to reproduce the fault
- Measure heater resistance at the sensor (engine cold) and compare to specification
- Backprobe connector with key ON and measure supply voltage to heater and control signal from DME
- Check related fuses/relays and vehicle grounds
Signal parameters
- Battery supply voltage to heater circuit: ~11–14.5 V with key ON/engine running
- Typical heater element resistance (zirconia narrowband upstream sensor): approximately 2–10 ohms at ambient — consult BMW spec for exact value
- Heater current draw typically around 0.5–3 A (varies by sensor type)
- Control method: DME may switch ground or supply (PWM or on/off); expect switching frequency or on/off states depending on engine temp
- Intermittent condition: signal may drop to 0 V or open circuit intermittently or show erratic PWM
Diagnostic algorithm
- Connect a full‑function scan tool. Confirm P1151 is present and note freeze frame and pending/history status. Check live heater status for Bank 2 Sensor 1 while cranking and during warm‑up.
- Perform a visual inspection of the sensor, connector and harness from the sensor back to the engine wiring junction. Look for corrosion, melted insulation, chafe points near exhaust, or pin damage.
- With ignition OFF, disconnect the sensor and measure heater resistance across the heater pins at the sensor. Compare to BMW spec. An open or infinite resistance indicates failed heater.
- With ignition ON (engine OFF), backprobe the connector and verify battery voltage is present at the supply terminal and a control return is present (ground switching or PWM) from the DME. If no supply, check fuses/relays and upstream wiring.
- With engine cold and then during warmup, monitor the control signal with a scope or multimeter set to view switching. Look for intermittent loss of supply or control switching. Wiggle the harness at suspect areas to reproduce the fault.
- Check continuity and resistance between the sensor connector and the DME pin to rule out high resistance or intermittent open. Inspect and test all relevant grounds.
- If wiring and connectors are good but the DME output is intermittent or stuck, verify with an independent power source and consult manufacturer procedures — avoid replacing DME as first step. Consider replacing sensor with OEM‑spec unit and retest if heater element out of spec.
- Repair any damaged wiring, replace corrupted connectors, replace the oxygen sensor if heater is failed, clear codes and perform drive cycle to verify the fault does not return and monitors complete.
- If fault returns after correct wiring and sensor replacement, test/replace DME driver per factory diagnostics.
Likely causes
- Corroded/loose connector or damaged wiring at Bank 2 Sensor 1 (most common)
- Failed heater element inside the sensor
- Intermittent open/short in harness from heat/chafing near exhaust
- Blown fuse or poor ground for heater circuit
- Faulty DME heater driver (less common)
Fault status
Status
P1151 — O2 Sensor Heater Circuit Signal Intermittent: Bank 2 Sensor 1. Intermittent heater circuit fault detected; check wiring, connector, fuse/relay and sensor heater element.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Workshop Manuals
Available brands with manuals
2
AUDI 11
6-speed manual gearbox 0B1, front-wheel drive — Workshop Manual (Edition 05.2014)
Workshop ManualAudi A3 (1997) – 1.6L 4-cylinder (2‑valve) Engine Mechanical Components Service Manual (AEH, AKL, APF) – Edition 07.2002
Workshop ManualAUDI A3 (2004) Workshop Manual — 2.0L FSI Turbo (4‑cyl, 4‑valve) Engine, Mechanics — Edition 03.2017
Workshop ManualAudi A3 2004 — Electrical System (Workshop Manual, Edition 02.2018)
Workshop ManualAudi A4 / A4 Cabriolet – 4.2 l V8 (5‑valve, timing chains) – Workshop Manual (Mechanics) – Edition 04.2007
Workshop ManualAudi A4 / A4 Cabriolet — Auxiliary Heater Workshop Manual (Edition 08.2004)
Workshop ManualAudi A4 / A4 Cabriolet (1.8T 4‑cyl turbo) — Motronic Injection & Ignition System Service Manual (Edition 01.2015)
Workshop ManualAudi A8 (2003) — Electrical System Workshop Manual (Edition 08.2014)
Workshop ManualAudi Q4 e-tron (Type F4) - Self-study Programme SSP 685
Workshop ManualAudi Q8 (2018) — Electrical System Workshop Manual (Edition 05.2019)
Workshop ManualAudi Servicing Manual — 7‑Speed Dual Clutch Transmission 0CJ / 0CL / 0CK / 0DN / 0DP / 0HL (Edition 05.2018)
Workshop ManualLAND ROVER 3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop ManualLand Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop ManualLand Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop ManualYour experience will help others
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Code
P1151
LAND ROVER
P — Powertrain
Lack of H02S-21 switch, sensor indicates lean
Views:
UK: 3
EN: 9
RU: 15
AI status
Completed
Completed
100%
Causes
- Open or intermittent wiring/connector between the sensor and DME
- Corroded or loose sensor connector or pin(s)
- Failed oxygen sensor heater element
- Blown fuse or faulty relay supplying heater circuit
- High circuit resistance from damaged wiring, poor ground, or contamination
- Intermittent or failed DME (heater driver) output
Symptoms
- Check Engine MIL illuminated (fault stored)
- Failure to reach O2 sensor operating temperature quickly — cold‑response emissions problems
- Evaporative/OBD readiness monitors fail or set ‘not ready’ for heated O2 sensor
- Possible increased tailpipe emissions or rough running during cold start
- Intermittent or sporadic diagnostic faults rather than constant code
What to check
- Read freeze frame and live data; confirm Bank 2 Sensor 1 heater status and if code is intermittent or current
- Visually inspect sensor connector and wiring for corrosion, damage, heat chafe, rodent damage or water intrusion
- Wiggle test harness and connector with scan tool connected to reproduce the fault
- Measure heater resistance at the sensor (engine cold) and compare to specification
- Backprobe connector with key ON and measure supply voltage to heater and control signal from DME
- Check related fuses/relays and vehicle grounds
Signal parameters
- Battery supply voltage to heater circuit: ~11–14.5 V with key ON/engine running
- Typical heater element resistance (zirconia narrowband upstream sensor): approximately 2–10 ohms at ambient — consult BMW spec for exact value
- Heater current draw typically around 0.5–3 A (varies by sensor type)
- Control method: DME may switch ground or supply (PWM or on/off); expect switching frequency or on/off states depending on engine temp
- Intermittent condition: signal may drop to 0 V or open circuit intermittently or show erratic PWM
Diagnostic algorithm
- Connect a full‑function scan tool. Confirm P1151 is present and note freeze frame and pending/history status. Check live heater status for Bank 2 Sensor 1 while cranking and during warm‑up.
- Perform a visual inspection of the sensor, connector and harness from the sensor back to the engine wiring junction. Look for corrosion, melted insulation, chafe points near exhaust, or pin damage.
- With ignition OFF, disconnect the sensor and measure heater resistance across the heater pins at the sensor. Compare to BMW spec. An open or infinite resistance indicates failed heater.
- With ignition ON (engine OFF), backprobe the connector and verify battery voltage is present at the supply terminal and a control return is present (ground switching or PWM) from the DME. If no supply, check fuses/relays and upstream wiring.
- With engine cold and then during warmup, monitor the control signal with a scope or multimeter set to view switching. Look for intermittent loss of supply or control switching. Wiggle the harness at suspect areas to reproduce the fault.
- Check continuity and resistance between the sensor connector and the DME pin to rule out high resistance or intermittent open. Inspect and test all relevant grounds.
- If wiring and connectors are good but the DME output is intermittent or stuck, verify with an independent power source and consult manufacturer procedures — avoid replacing DME as first step. Consider replacing sensor with OEM‑spec unit and retest if heater element out of spec.
- Repair any damaged wiring, replace corrupted connectors, replace the oxygen sensor if heater is failed, clear codes and perform drive cycle to verify the fault does not return and monitors complete.
- If fault returns after correct wiring and sensor replacement, test/replace DME driver per factory diagnostics.
Likely causes
- Corroded/loose connector or damaged wiring at Bank 2 Sensor 1 (most common)
- Failed heater element inside the sensor
- Intermittent open/short in harness from heat/chafing near exhaust
- Blown fuse or poor ground for heater circuit
- Faulty DME heater driver (less common)
Fault status
Status
P1151 — O2 Sensor Heater Circuit Signal Intermittent: Bank 2 Sensor 1. Intermittent heater circuit fault detected; check wiring, connector, fuse/relay and sensor heater element.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Workshop Manuals
Repair manuals for LAND ROVER
3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop ManualLand Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop ManualLand Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop ManualYour experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
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👍 Like
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Send to email
Code
P1151
LINCOLN
P — Powertrain
Lack of Upstream Heated Oxygen Sensor Switch Sensor Indicates Lean Bank 2
Views:
UK: 21
EN: 47
RU: 32
AI status
Completed
Completed
100%
Causes
- Open or intermittent wiring/connector between the sensor and DME
- Corroded or loose sensor connector or pin(s)
- Failed oxygen sensor heater element
- Blown fuse or faulty relay supplying heater circuit
- High circuit resistance from damaged wiring, poor ground, or contamination
- Intermittent or failed DME (heater driver) output
Symptoms
- Check Engine MIL illuminated (fault stored)
- Failure to reach O2 sensor operating temperature quickly — cold‑response emissions problems
- Evaporative/OBD readiness monitors fail or set ‘not ready’ for heated O2 sensor
- Possible increased tailpipe emissions or rough running during cold start
- Intermittent or sporadic diagnostic faults rather than constant code
What to check
- Read freeze frame and live data; confirm Bank 2 Sensor 1 heater status and if code is intermittent or current
- Visually inspect sensor connector and wiring for corrosion, damage, heat chafe, rodent damage or water intrusion
- Wiggle test harness and connector with scan tool connected to reproduce the fault
- Measure heater resistance at the sensor (engine cold) and compare to specification
- Backprobe connector with key ON and measure supply voltage to heater and control signal from DME
- Check related fuses/relays and vehicle grounds
Signal parameters
- Battery supply voltage to heater circuit: ~11–14.5 V with key ON/engine running
- Typical heater element resistance (zirconia narrowband upstream sensor): approximately 2–10 ohms at ambient — consult BMW spec for exact value
- Heater current draw typically around 0.5–3 A (varies by sensor type)
- Control method: DME may switch ground or supply (PWM or on/off); expect switching frequency or on/off states depending on engine temp
- Intermittent condition: signal may drop to 0 V or open circuit intermittently or show erratic PWM
Diagnostic algorithm
- Connect a full‑function scan tool. Confirm P1151 is present and note freeze frame and pending/history status. Check live heater status for Bank 2 Sensor 1 while cranking and during warm‑up.
- Perform a visual inspection of the sensor, connector and harness from the sensor back to the engine wiring junction. Look for corrosion, melted insulation, chafe points near exhaust, or pin damage.
- With ignition OFF, disconnect the sensor and measure heater resistance across the heater pins at the sensor. Compare to BMW spec. An open or infinite resistance indicates failed heater.
- With ignition ON (engine OFF), backprobe the connector and verify battery voltage is present at the supply terminal and a control return is present (ground switching or PWM) from the DME. If no supply, check fuses/relays and upstream wiring.
- With engine cold and then during warmup, monitor the control signal with a scope or multimeter set to view switching. Look for intermittent loss of supply or control switching. Wiggle the harness at suspect areas to reproduce the fault.
- Check continuity and resistance between the sensor connector and the DME pin to rule out high resistance or intermittent open. Inspect and test all relevant grounds.
- If wiring and connectors are good but the DME output is intermittent or stuck, verify with an independent power source and consult manufacturer procedures — avoid replacing DME as first step. Consider replacing sensor with OEM‑spec unit and retest if heater element out of spec.
- Repair any damaged wiring, replace corrupted connectors, replace the oxygen sensor if heater is failed, clear codes and perform drive cycle to verify the fault does not return and monitors complete.
- If fault returns after correct wiring and sensor replacement, test/replace DME driver per factory diagnostics.
Likely causes
- Corroded/loose connector or damaged wiring at Bank 2 Sensor 1 (most common)
- Failed heater element inside the sensor
- Intermittent open/short in harness from heat/chafing near exhaust
- Blown fuse or poor ground for heater circuit
- Faulty DME heater driver (less common)
Fault status
Status
P1151 — O2 Sensor Heater Circuit Signal Intermittent: Bank 2 Sensor 1. Intermittent heater circuit fault detected; check wiring, connector, fuse/relay and sensor heater element.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Your experience will help others
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Send to email
Code
P1151
MAZDA
P — Powertrain
HO2S Bank 2 Sensor 1 Signal Below 0.45v AF Ratio Too Lean
Views:
UK: 21
EN: 46
RU: 30
AI status
Completed
Completed
100%
Causes
- Open or intermittent wiring/connector between the sensor and DME
- Corroded or loose sensor connector or pin(s)
- Failed oxygen sensor heater element
- Blown fuse or faulty relay supplying heater circuit
- High circuit resistance from damaged wiring, poor ground, or contamination
- Intermittent or failed DME (heater driver) output
Symptoms
- Check Engine MIL illuminated (fault stored)
- Failure to reach O2 sensor operating temperature quickly — cold‑response emissions problems
- Evaporative/OBD readiness monitors fail or set ‘not ready’ for heated O2 sensor
- Possible increased tailpipe emissions or rough running during cold start
- Intermittent or sporadic diagnostic faults rather than constant code
What to check
- Read freeze frame and live data; confirm Bank 2 Sensor 1 heater status and if code is intermittent or current
- Visually inspect sensor connector and wiring for corrosion, damage, heat chafe, rodent damage or water intrusion
- Wiggle test harness and connector with scan tool connected to reproduce the fault
- Measure heater resistance at the sensor (engine cold) and compare to specification
- Backprobe connector with key ON and measure supply voltage to heater and control signal from DME
- Check related fuses/relays and vehicle grounds
Signal parameters
- Battery supply voltage to heater circuit: ~11–14.5 V with key ON/engine running
- Typical heater element resistance (zirconia narrowband upstream sensor): approximately 2–10 ohms at ambient — consult BMW spec for exact value
- Heater current draw typically around 0.5–3 A (varies by sensor type)
- Control method: DME may switch ground or supply (PWM or on/off); expect switching frequency or on/off states depending on engine temp
- Intermittent condition: signal may drop to 0 V or open circuit intermittently or show erratic PWM
Diagnostic algorithm
- Connect a full‑function scan tool. Confirm P1151 is present and note freeze frame and pending/history status. Check live heater status for Bank 2 Sensor 1 while cranking and during warm‑up.
- Perform a visual inspection of the sensor, connector and harness from the sensor back to the engine wiring junction. Look for corrosion, melted insulation, chafe points near exhaust, or pin damage.
- With ignition OFF, disconnect the sensor and measure heater resistance across the heater pins at the sensor. Compare to BMW spec. An open or infinite resistance indicates failed heater.
- With ignition ON (engine OFF), backprobe the connector and verify battery voltage is present at the supply terminal and a control return is present (ground switching or PWM) from the DME. If no supply, check fuses/relays and upstream wiring.
- With engine cold and then during warmup, monitor the control signal with a scope or multimeter set to view switching. Look for intermittent loss of supply or control switching. Wiggle the harness at suspect areas to reproduce the fault.
- Check continuity and resistance between the sensor connector and the DME pin to rule out high resistance or intermittent open. Inspect and test all relevant grounds.
- If wiring and connectors are good but the DME output is intermittent or stuck, verify with an independent power source and consult manufacturer procedures — avoid replacing DME as first step. Consider replacing sensor with OEM‑spec unit and retest if heater element out of spec.
- Repair any damaged wiring, replace corrupted connectors, replace the oxygen sensor if heater is failed, clear codes and perform drive cycle to verify the fault does not return and monitors complete.
- If fault returns after correct wiring and sensor replacement, test/replace DME driver per factory diagnostics.
Likely causes
- Corroded/loose connector or damaged wiring at Bank 2 Sensor 1 (most common)
- Failed heater element inside the sensor
- Intermittent open/short in harness from heat/chafing near exhaust
- Blown fuse or poor ground for heater circuit
- Faulty DME heater driver (less common)
Fault status
Status
P1151 — O2 Sensor Heater Circuit Signal Intermittent: Bank 2 Sensor 1. Intermittent heater circuit fault detected; check wiring, connector, fuse/relay and sensor heater element.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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Code
P1151
MERCURY
P — Powertrain
Lack of Upstream Heated Oxygen Sensor Switch Sensor Indicates Lean Bank 2
Views:
UK: 21
EN: 60
RU: 36
AI status
Completed
Completed
100%
Causes
- Open or intermittent wiring/connector between the sensor and DME
- Corroded or loose sensor connector or pin(s)
- Failed oxygen sensor heater element
- Blown fuse or faulty relay supplying heater circuit
- High circuit resistance from damaged wiring, poor ground, or contamination
- Intermittent or failed DME (heater driver) output
Symptoms
- Check Engine MIL illuminated (fault stored)
- Failure to reach O2 sensor operating temperature quickly — cold‑response emissions problems
- Evaporative/OBD readiness monitors fail or set ‘not ready’ for heated O2 sensor
- Possible increased tailpipe emissions or rough running during cold start
- Intermittent or sporadic diagnostic faults rather than constant code
What to check
- Read freeze frame and live data; confirm Bank 2 Sensor 1 heater status and if code is intermittent or current
- Visually inspect sensor connector and wiring for corrosion, damage, heat chafe, rodent damage or water intrusion
- Wiggle test harness and connector with scan tool connected to reproduce the fault
- Measure heater resistance at the sensor (engine cold) and compare to specification
- Backprobe connector with key ON and measure supply voltage to heater and control signal from DME
- Check related fuses/relays and vehicle grounds
Signal parameters
- Battery supply voltage to heater circuit: ~11–14.5 V with key ON/engine running
- Typical heater element resistance (zirconia narrowband upstream sensor): approximately 2–10 ohms at ambient — consult BMW spec for exact value
- Heater current draw typically around 0.5–3 A (varies by sensor type)
- Control method: DME may switch ground or supply (PWM or on/off); expect switching frequency or on/off states depending on engine temp
- Intermittent condition: signal may drop to 0 V or open circuit intermittently or show erratic PWM
Diagnostic algorithm
- Connect a full‑function scan tool. Confirm P1151 is present and note freeze frame and pending/history status. Check live heater status for Bank 2 Sensor 1 while cranking and during warm‑up.
- Perform a visual inspection of the sensor, connector and harness from the sensor back to the engine wiring junction. Look for corrosion, melted insulation, chafe points near exhaust, or pin damage.
- With ignition OFF, disconnect the sensor and measure heater resistance across the heater pins at the sensor. Compare to BMW spec. An open or infinite resistance indicates failed heater.
- With ignition ON (engine OFF), backprobe the connector and verify battery voltage is present at the supply terminal and a control return is present (ground switching or PWM) from the DME. If no supply, check fuses/relays and upstream wiring.
- With engine cold and then during warmup, monitor the control signal with a scope or multimeter set to view switching. Look for intermittent loss of supply or control switching. Wiggle the harness at suspect areas to reproduce the fault.
- Check continuity and resistance between the sensor connector and the DME pin to rule out high resistance or intermittent open. Inspect and test all relevant grounds.
- If wiring and connectors are good but the DME output is intermittent or stuck, verify with an independent power source and consult manufacturer procedures — avoid replacing DME as first step. Consider replacing sensor with OEM‑spec unit and retest if heater element out of spec.
- Repair any damaged wiring, replace corrupted connectors, replace the oxygen sensor if heater is failed, clear codes and perform drive cycle to verify the fault does not return and monitors complete.
- If fault returns after correct wiring and sensor replacement, test/replace DME driver per factory diagnostics.
Likely causes
- Corroded/loose connector or damaged wiring at Bank 2 Sensor 1 (most common)
- Failed heater element inside the sensor
- Intermittent open/short in harness from heat/chafing near exhaust
- Blown fuse or poor ground for heater circuit
- Faulty DME heater driver (less common)
Fault status
Status
P1151 — O2 Sensor Heater Circuit Signal Intermittent: Bank 2 Sensor 1. Intermittent heater circuit fault detected; check wiring, connector, fuse/relay and sensor heater element.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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Code
P1151
Other
P — Powertrain
Lack Of HO2S21 Switch - Sensor Indicates Lean
Views:
UK: 19
EN: 54
RU: 30
AI status
Completed
Completed
100%
Causes
- Open or intermittent wiring/connector between the sensor and DME
- Corroded or loose sensor connector or pin(s)
- Failed oxygen sensor heater element
- Blown fuse or faulty relay supplying heater circuit
- High circuit resistance from damaged wiring, poor ground, or contamination
- Intermittent or failed DME (heater driver) output
Symptoms
- Check Engine MIL illuminated (fault stored)
- Failure to reach O2 sensor operating temperature quickly — cold‑response emissions problems
- Evaporative/OBD readiness monitors fail or set ‘not ready’ for heated O2 sensor
- Possible increased tailpipe emissions or rough running during cold start
- Intermittent or sporadic diagnostic faults rather than constant code
What to check
- Read freeze frame and live data; confirm Bank 2 Sensor 1 heater status and if code is intermittent or current
- Visually inspect sensor connector and wiring for corrosion, damage, heat chafe, rodent damage or water intrusion
- Wiggle test harness and connector with scan tool connected to reproduce the fault
- Measure heater resistance at the sensor (engine cold) and compare to specification
- Backprobe connector with key ON and measure supply voltage to heater and control signal from DME
- Check related fuses/relays and vehicle grounds
Signal parameters
- Battery supply voltage to heater circuit: ~11–14.5 V with key ON/engine running
- Typical heater element resistance (zirconia narrowband upstream sensor): approximately 2–10 ohms at ambient — consult BMW spec for exact value
- Heater current draw typically around 0.5–3 A (varies by sensor type)
- Control method: DME may switch ground or supply (PWM or on/off); expect switching frequency or on/off states depending on engine temp
- Intermittent condition: signal may drop to 0 V or open circuit intermittently or show erratic PWM
Diagnostic algorithm
- Connect a full‑function scan tool. Confirm P1151 is present and note freeze frame and pending/history status. Check live heater status for Bank 2 Sensor 1 while cranking and during warm‑up.
- Perform a visual inspection of the sensor, connector and harness from the sensor back to the engine wiring junction. Look for corrosion, melted insulation, chafe points near exhaust, or pin damage.
- With ignition OFF, disconnect the sensor and measure heater resistance across the heater pins at the sensor. Compare to BMW spec. An open or infinite resistance indicates failed heater.
- With ignition ON (engine OFF), backprobe the connector and verify battery voltage is present at the supply terminal and a control return is present (ground switching or PWM) from the DME. If no supply, check fuses/relays and upstream wiring.
- With engine cold and then during warmup, monitor the control signal with a scope or multimeter set to view switching. Look for intermittent loss of supply or control switching. Wiggle the harness at suspect areas to reproduce the fault.
- Check continuity and resistance between the sensor connector and the DME pin to rule out high resistance or intermittent open. Inspect and test all relevant grounds.
- If wiring and connectors are good but the DME output is intermittent or stuck, verify with an independent power source and consult manufacturer procedures — avoid replacing DME as first step. Consider replacing sensor with OEM‑spec unit and retest if heater element out of spec.
- Repair any damaged wiring, replace corrupted connectors, replace the oxygen sensor if heater is failed, clear codes and perform drive cycle to verify the fault does not return and monitors complete.
- If fault returns after correct wiring and sensor replacement, test/replace DME driver per factory diagnostics.
Likely causes
- Corroded/loose connector or damaged wiring at Bank 2 Sensor 1 (most common)
- Failed heater element inside the sensor
- Intermittent open/short in harness from heat/chafing near exhaust
- Blown fuse or poor ground for heater circuit
- Faulty DME heater driver (less common)
Fault status
Status
P1151 — O2 Sensor Heater Circuit Signal Intermittent: Bank 2 Sensor 1. Intermittent heater circuit fault detected; check wiring, connector, fuse/relay and sensor heater element.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Workshop Manuals
Available brands with manuals
2
AUDI 11
6-speed manual gearbox 0B1, front-wheel drive — Workshop Manual (Edition 05.2014)
Workshop ManualAudi A3 (1997) – 1.6L 4-cylinder (2‑valve) Engine Mechanical Components Service Manual (AEH, AKL, APF) – Edition 07.2002
Workshop ManualAUDI A3 (2004) Workshop Manual — 2.0L FSI Turbo (4‑cyl, 4‑valve) Engine, Mechanics — Edition 03.2017
Workshop ManualAudi A3 2004 — Electrical System (Workshop Manual, Edition 02.2018)
Workshop ManualAudi A4 / A4 Cabriolet – 4.2 l V8 (5‑valve, timing chains) – Workshop Manual (Mechanics) – Edition 04.2007
Workshop ManualAudi A4 / A4 Cabriolet — Auxiliary Heater Workshop Manual (Edition 08.2004)
Workshop ManualAudi A4 / A4 Cabriolet (1.8T 4‑cyl turbo) — Motronic Injection & Ignition System Service Manual (Edition 01.2015)
Workshop ManualAudi A8 (2003) — Electrical System Workshop Manual (Edition 08.2014)
Workshop ManualAudi Q4 e-tron (Type F4) - Self-study Programme SSP 685
Workshop ManualAudi Q8 (2018) — Electrical System Workshop Manual (Edition 05.2019)
Workshop ManualAudi Servicing Manual — 7‑Speed Dual Clutch Transmission 0CJ / 0CL / 0CK / 0DN / 0DP / 0HL (Edition 05.2018)
Workshop ManualLAND ROVER 3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop ManualLand Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop ManualLand Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop ManualYour experience will help others
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Code
P1151
SUBARU
P — Powertrain
Rear Oxygen Sensor Heater Circuit High Input
Views:
UK: 21
EN: 56
RU: 35
AI status
Completed
Completed
100%
Causes
- Open or intermittent wiring/connector between the sensor and DME
- Corroded or loose sensor connector or pin(s)
- Failed oxygen sensor heater element
- Blown fuse or faulty relay supplying heater circuit
- High circuit resistance from damaged wiring, poor ground, or contamination
- Intermittent or failed DME (heater driver) output
Symptoms
- Check Engine MIL illuminated (fault stored)
- Failure to reach O2 sensor operating temperature quickly — cold‑response emissions problems
- Evaporative/OBD readiness monitors fail or set ‘not ready’ for heated O2 sensor
- Possible increased tailpipe emissions or rough running during cold start
- Intermittent or sporadic diagnostic faults rather than constant code
What to check
- Read freeze frame and live data; confirm Bank 2 Sensor 1 heater status and if code is intermittent or current
- Visually inspect sensor connector and wiring for corrosion, damage, heat chafe, rodent damage or water intrusion
- Wiggle test harness and connector with scan tool connected to reproduce the fault
- Measure heater resistance at the sensor (engine cold) and compare to specification
- Backprobe connector with key ON and measure supply voltage to heater and control signal from DME
- Check related fuses/relays and vehicle grounds
Signal parameters
- Battery supply voltage to heater circuit: ~11–14.5 V with key ON/engine running
- Typical heater element resistance (zirconia narrowband upstream sensor): approximately 2–10 ohms at ambient — consult BMW spec for exact value
- Heater current draw typically around 0.5–3 A (varies by sensor type)
- Control method: DME may switch ground or supply (PWM or on/off); expect switching frequency or on/off states depending on engine temp
- Intermittent condition: signal may drop to 0 V or open circuit intermittently or show erratic PWM
Diagnostic algorithm
- Connect a full‑function scan tool. Confirm P1151 is present and note freeze frame and pending/history status. Check live heater status for Bank 2 Sensor 1 while cranking and during warm‑up.
- Perform a visual inspection of the sensor, connector and harness from the sensor back to the engine wiring junction. Look for corrosion, melted insulation, chafe points near exhaust, or pin damage.
- With ignition OFF, disconnect the sensor and measure heater resistance across the heater pins at the sensor. Compare to BMW spec. An open or infinite resistance indicates failed heater.
- With ignition ON (engine OFF), backprobe the connector and verify battery voltage is present at the supply terminal and a control return is present (ground switching or PWM) from the DME. If no supply, check fuses/relays and upstream wiring.
- With engine cold and then during warmup, monitor the control signal with a scope or multimeter set to view switching. Look for intermittent loss of supply or control switching. Wiggle the harness at suspect areas to reproduce the fault.
- Check continuity and resistance between the sensor connector and the DME pin to rule out high resistance or intermittent open. Inspect and test all relevant grounds.
- If wiring and connectors are good but the DME output is intermittent or stuck, verify with an independent power source and consult manufacturer procedures — avoid replacing DME as first step. Consider replacing sensor with OEM‑spec unit and retest if heater element out of spec.
- Repair any damaged wiring, replace corrupted connectors, replace the oxygen sensor if heater is failed, clear codes and perform drive cycle to verify the fault does not return and monitors complete.
- If fault returns after correct wiring and sensor replacement, test/replace DME driver per factory diagnostics.
Likely causes
- Corroded/loose connector or damaged wiring at Bank 2 Sensor 1 (most common)
- Failed heater element inside the sensor
- Intermittent open/short in harness from heat/chafing near exhaust
- Blown fuse or poor ground for heater circuit
- Faulty DME heater driver (less common)
Fault status
Status
P1151 — O2 Sensor Heater Circuit Signal Intermittent: Bank 2 Sensor 1. Intermittent heater circuit fault detected; check wiring, connector, fuse/relay and sensor heater element.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Your experience will help others
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Was this AI description helpful?
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Send to email
Code
P1151
VOLKSWAGEN
P — Powertrain
Bank 1 Long Term Fuel Trim Range 1 Lower Lean Limit Exceeded
Views:
UK: 20
EN: 48
RU: 31
AI status
Completed
Completed
100%
Causes
- Open or intermittent wiring/connector between the sensor and DME
- Corroded or loose sensor connector or pin(s)
- Failed oxygen sensor heater element
- Blown fuse or faulty relay supplying heater circuit
- High circuit resistance from damaged wiring, poor ground, or contamination
- Intermittent or failed DME (heater driver) output
Symptoms
- Check Engine MIL illuminated (fault stored)
- Failure to reach O2 sensor operating temperature quickly — cold‑response emissions problems
- Evaporative/OBD readiness monitors fail or set ‘not ready’ for heated O2 sensor
- Possible increased tailpipe emissions or rough running during cold start
- Intermittent or sporadic diagnostic faults rather than constant code
What to check
- Read freeze frame and live data; confirm Bank 2 Sensor 1 heater status and if code is intermittent or current
- Visually inspect sensor connector and wiring for corrosion, damage, heat chafe, rodent damage or water intrusion
- Wiggle test harness and connector with scan tool connected to reproduce the fault
- Measure heater resistance at the sensor (engine cold) and compare to specification
- Backprobe connector with key ON and measure supply voltage to heater and control signal from DME
- Check related fuses/relays and vehicle grounds
Signal parameters
- Battery supply voltage to heater circuit: ~11–14.5 V with key ON/engine running
- Typical heater element resistance (zirconia narrowband upstream sensor): approximately 2–10 ohms at ambient — consult BMW spec for exact value
- Heater current draw typically around 0.5–3 A (varies by sensor type)
- Control method: DME may switch ground or supply (PWM or on/off); expect switching frequency or on/off states depending on engine temp
- Intermittent condition: signal may drop to 0 V or open circuit intermittently or show erratic PWM
Diagnostic algorithm
- Connect a full‑function scan tool. Confirm P1151 is present and note freeze frame and pending/history status. Check live heater status for Bank 2 Sensor 1 while cranking and during warm‑up.
- Perform a visual inspection of the sensor, connector and harness from the sensor back to the engine wiring junction. Look for corrosion, melted insulation, chafe points near exhaust, or pin damage.
- With ignition OFF, disconnect the sensor and measure heater resistance across the heater pins at the sensor. Compare to BMW spec. An open or infinite resistance indicates failed heater.
- With ignition ON (engine OFF), backprobe the connector and verify battery voltage is present at the supply terminal and a control return is present (ground switching or PWM) from the DME. If no supply, check fuses/relays and upstream wiring.
- With engine cold and then during warmup, monitor the control signal with a scope or multimeter set to view switching. Look for intermittent loss of supply or control switching. Wiggle the harness at suspect areas to reproduce the fault.
- Check continuity and resistance between the sensor connector and the DME pin to rule out high resistance or intermittent open. Inspect and test all relevant grounds.
- If wiring and connectors are good but the DME output is intermittent or stuck, verify with an independent power source and consult manufacturer procedures — avoid replacing DME as first step. Consider replacing sensor with OEM‑spec unit and retest if heater element out of spec.
- Repair any damaged wiring, replace corrupted connectors, replace the oxygen sensor if heater is failed, clear codes and perform drive cycle to verify the fault does not return and monitors complete.
- If fault returns after correct wiring and sensor replacement, test/replace DME driver per factory diagnostics.
Likely causes
- Corroded/loose connector or damaged wiring at Bank 2 Sensor 1 (most common)
- Failed heater element inside the sensor
- Intermittent open/short in harness from heat/chafing near exhaust
- Blown fuse or poor ground for heater circuit
- Faulty DME heater driver (less common)
Fault status
Status
P1151 — O2 Sensor Heater Circuit Signal Intermittent: Bank 2 Sensor 1. Intermittent heater circuit fault detected; check wiring, connector, fuse/relay and sensor heater element.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email