Code
P0151
Generic
P — Powertrain
O2 Sensor Circuit Low Voltage Bank 2 Sensor 1
AI status
Completed
Completed
100%
Causes
- Faulty Bank 2 Sensor 1 (upstream O2 sensor)
- Wiring shorted to ground on the sensor signal circuit
- Open or corroded connector or poor sensor ground
- Exhaust leak upstream of the sensor
- Fuel delivery lean condition (low fuel pressure, clogged injector, intake leak)
- Sensor contamination (oil, coolant, silicone, sulfur)
Symptoms
- Check Engine Light (MIL) illuminated
- Poor fuel economy
- Rough idle or hesitation under load
- Difficulty passing emissions test
- Persistent lean fuel trims (positive long‑term fuel trim)
What to check
- Read and record all stored DTCs and freeze‑frame data
- Monitor live data: Bank 2 Sensor 1 voltage, heater status, short‑term and long‑term fuel trims
- Verify engine is at normal operating temperature before testing (sensor must be hot)
- Check for related codes (fuel trim, misfire, fuel pressure)
- Visually inspect sensor, connector and wiring for damage, corrosion, heat damage, or rubbing
- Perform a smoke test for vacuum/exhaust leaks on Bank 2 side
Signal parameters
- Expected zirconia O2 sensor voltage: approximately 0.1–0.9 V (lean ≈0.1–0.3 V, rich ≈0.6–0.9 V)
- Normal upstream switching: frequent transition between low and high as closed‑loop control operates
- P0151 symptom: persistent low/stuck voltage (near 0.1–0.2 V) or no switching
- Heater circuit: battery voltage applied with PCM control when key on/engine off; typical heater resistance often 2–20 Ω depending on sensor type (refer to vehicle spec)
Diagnostic algorithm
- Verify readiness and conditions: retrieve codes and freeze frame, warm engine to normal operating temperature, clear code and attempt to reproduce.
- Monitor live data: confirm Bank 2 Sensor 1 voltage stays low (
- Check fuel trims: large positive LTFT on Bank 2 supports a true lean condition; if trims are normal, suspect sensor/electrical fault.
- Inspect wiring/connectors: visually and physically check harness at the sensor for damage, corrosion, or heat chafe; repair any issues.
- Test sensor heater: with connector disconnected, measure heater resistance and check for supply voltage and PCM switching on power‑up; replace sensor if heater open or no voltage present from PCM when expected.
- Signal circuit test: backprobe signal wire and measure voltage; if the wire is held near ground, trace for short to chassis; disconnect sensor — if voltage jumps or behaves differently, suspect wiring or PCM.
- Check for mechanical causes of lean: perform smoke test for vacuum/exhaust leaks, inspect intake gasket/seal on Bank 2 side, and test fuel pressure and injector operation.
- Replace sensor only after confirming wiring and system conditions are good. After repair clear codes and road test through a full drive cycle to verify the code does not return.
Likely causes
- Failed or aging upstream O2 sensor on Bank 2
- Signal wire short to ground or chafed insulation at harness/connector
- Intake vacuum leak or exhaust leak on Bank 2 side causing a lean reading
- Low fuel pressure or restricted injector feeding Bank 2 cylinders
Fault status
Status
PCM detected the Bank 2 Sensor 1 oxygen sensor signal below the expected threshold for the required time or the sensor output is not switching as expected, indicating a low voltage (lean) signal or electrical fault in the sensor circuit.
Repair difficulty: Medium
Diagnostic time: 0.5-2.5 hours
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Repair manuals
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Code
P0151
GWM
P — Powertrain
- Oxygen sensor circuit low voltage (bank 2, sensor 1)
AI status
Completed
Completed
100%
Causes
- Faulty Bank 2 Sensor 1 (upstream O2 sensor)
- Wiring shorted to ground on the sensor signal circuit
- Open or corroded connector or poor sensor ground
- Exhaust leak upstream of the sensor
- Fuel delivery lean condition (low fuel pressure, clogged injector, intake leak)
- Sensor contamination (oil, coolant, silicone, sulfur)
Symptoms
- Check Engine Light (MIL) illuminated
- Poor fuel economy
- Rough idle or hesitation under load
- Difficulty passing emissions test
- Persistent lean fuel trims (positive long‑term fuel trim)
What to check
- Read and record all stored DTCs and freeze‑frame data
- Monitor live data: Bank 2 Sensor 1 voltage, heater status, short‑term and long‑term fuel trims
- Verify engine is at normal operating temperature before testing (sensor must be hot)
- Check for related codes (fuel trim, misfire, fuel pressure)
- Visually inspect sensor, connector and wiring for damage, corrosion, heat damage, or rubbing
- Perform a smoke test for vacuum/exhaust leaks on Bank 2 side
Signal parameters
- Expected zirconia O2 sensor voltage: approximately 0.1–0.9 V (lean ≈0.1–0.3 V, rich ≈0.6–0.9 V)
- Normal upstream switching: frequent transition between low and high as closed‑loop control operates
- P0151 symptom: persistent low/stuck voltage (near 0.1–0.2 V) or no switching
- Heater circuit: battery voltage applied with PCM control when key on/engine off; typical heater resistance often 2–20 Ω depending on sensor type (refer to vehicle spec)
Diagnostic algorithm
- Verify readiness and conditions: retrieve codes and freeze frame, warm engine to normal operating temperature, clear code and attempt to reproduce.
- Monitor live data: confirm Bank 2 Sensor 1 voltage stays low (
- Check fuel trims: large positive LTFT on Bank 2 supports a true lean condition; if trims are normal, suspect sensor/electrical fault.
- Inspect wiring/connectors: visually and physically check harness at the sensor for damage, corrosion, or heat chafe; repair any issues.
- Test sensor heater: with connector disconnected, measure heater resistance and check for supply voltage and PCM switching on power‑up; replace sensor if heater open or no voltage present from PCM when expected.
- Signal circuit test: backprobe signal wire and measure voltage; if the wire is held near ground, trace for short to chassis; disconnect sensor — if voltage jumps or behaves differently, suspect wiring or PCM.
- Check for mechanical causes of lean: perform smoke test for vacuum/exhaust leaks, inspect intake gasket/seal on Bank 2 side, and test fuel pressure and injector operation.
- Replace sensor only after confirming wiring and system conditions are good. After repair clear codes and road test through a full drive cycle to verify the code does not return.
Likely causes
- Failed or aging upstream O2 sensor on Bank 2
- Signal wire short to ground or chafed insulation at harness/connector
- Intake vacuum leak or exhaust leak on Bank 2 side causing a lean reading
- Low fuel pressure or restricted injector feeding Bank 2 cylinders
Fault status
Status
PCM detected the Bank 2 Sensor 1 oxygen sensor signal below the expected threshold for the required time or the sensor output is not switching as expected, indicating a low voltage (lean) signal or electrical fault in the sensor circuit.
Repair difficulty: Medium
Diagnostic time: 0.5-2.5 hours
Similar codes
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Code
P0151
HUMMER
P — Powertrain
Heated Oxygen Sensor (HO2S) Circuit Low Voltage Bank 2 Sensor 1
AI status
Completed
Completed
100%
Causes
- Faulty Bank 2 Sensor 1 (upstream O2 sensor)
- Wiring shorted to ground on the sensor signal circuit
- Open or corroded connector or poor sensor ground
- Exhaust leak upstream of the sensor
- Fuel delivery lean condition (low fuel pressure, clogged injector, intake leak)
- Sensor contamination (oil, coolant, silicone, sulfur)
Symptoms
- Check Engine Light (MIL) illuminated
- Poor fuel economy
- Rough idle or hesitation under load
- Difficulty passing emissions test
- Persistent lean fuel trims (positive long‑term fuel trim)
What to check
- Read and record all stored DTCs and freeze‑frame data
- Monitor live data: Bank 2 Sensor 1 voltage, heater status, short‑term and long‑term fuel trims
- Verify engine is at normal operating temperature before testing (sensor must be hot)
- Check for related codes (fuel trim, misfire, fuel pressure)
- Visually inspect sensor, connector and wiring for damage, corrosion, heat damage, or rubbing
- Perform a smoke test for vacuum/exhaust leaks on Bank 2 side
Signal parameters
- Expected zirconia O2 sensor voltage: approximately 0.1–0.9 V (lean ≈0.1–0.3 V, rich ≈0.6–0.9 V)
- Normal upstream switching: frequent transition between low and high as closed‑loop control operates
- P0151 symptom: persistent low/stuck voltage (near 0.1–0.2 V) or no switching
- Heater circuit: battery voltage applied with PCM control when key on/engine off; typical heater resistance often 2–20 Ω depending on sensor type (refer to vehicle spec)
Diagnostic algorithm
- Verify readiness and conditions: retrieve codes and freeze frame, warm engine to normal operating temperature, clear code and attempt to reproduce.
- Monitor live data: confirm Bank 2 Sensor 1 voltage stays low (
- Check fuel trims: large positive LTFT on Bank 2 supports a true lean condition; if trims are normal, suspect sensor/electrical fault.
- Inspect wiring/connectors: visually and physically check harness at the sensor for damage, corrosion, or heat chafe; repair any issues.
- Test sensor heater: with connector disconnected, measure heater resistance and check for supply voltage and PCM switching on power‑up; replace sensor if heater open or no voltage present from PCM when expected.
- Signal circuit test: backprobe signal wire and measure voltage; if the wire is held near ground, trace for short to chassis; disconnect sensor — if voltage jumps or behaves differently, suspect wiring or PCM.
- Check for mechanical causes of lean: perform smoke test for vacuum/exhaust leaks, inspect intake gasket/seal on Bank 2 side, and test fuel pressure and injector operation.
- Replace sensor only after confirming wiring and system conditions are good. After repair clear codes and road test through a full drive cycle to verify the code does not return.
Likely causes
- Failed or aging upstream O2 sensor on Bank 2
- Signal wire short to ground or chafed insulation at harness/connector
- Intake vacuum leak or exhaust leak on Bank 2 side causing a lean reading
- Low fuel pressure or restricted injector feeding Bank 2 cylinders
Fault status
Status
PCM detected the Bank 2 Sensor 1 oxygen sensor signal below the expected threshold for the required time or the sensor output is not switching as expected, indicating a low voltage (lean) signal or electrical fault in the sensor circuit.
Repair difficulty: Medium
Diagnostic time: 0.5-2.5 hours
Similar codes
Repair manuals
Manual library for HUMMER
138
Browse 138 HUMMER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.
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Code
P0151
LAND ROVER
P — Powertrain
Oxygen sensor circuit low voltage (bank 2 sensor 1)
AI status
Completed
Completed
100%
Causes
- Faulty Bank 2 Sensor 1 (upstream O2 sensor)
- Wiring shorted to ground on the sensor signal circuit
- Open or corroded connector or poor sensor ground
- Exhaust leak upstream of the sensor
- Fuel delivery lean condition (low fuel pressure, clogged injector, intake leak)
- Sensor contamination (oil, coolant, silicone, sulfur)
Symptoms
- Check Engine Light (MIL) illuminated
- Poor fuel economy
- Rough idle or hesitation under load
- Difficulty passing emissions test
- Persistent lean fuel trims (positive long‑term fuel trim)
What to check
- Read and record all stored DTCs and freeze‑frame data
- Monitor live data: Bank 2 Sensor 1 voltage, heater status, short‑term and long‑term fuel trims
- Verify engine is at normal operating temperature before testing (sensor must be hot)
- Check for related codes (fuel trim, misfire, fuel pressure)
- Visually inspect sensor, connector and wiring for damage, corrosion, heat damage, or rubbing
- Perform a smoke test for vacuum/exhaust leaks on Bank 2 side
Signal parameters
- Expected zirconia O2 sensor voltage: approximately 0.1–0.9 V (lean ≈0.1–0.3 V, rich ≈0.6–0.9 V)
- Normal upstream switching: frequent transition between low and high as closed‑loop control operates
- P0151 symptom: persistent low/stuck voltage (near 0.1–0.2 V) or no switching
- Heater circuit: battery voltage applied with PCM control when key on/engine off; typical heater resistance often 2–20 Ω depending on sensor type (refer to vehicle spec)
Diagnostic algorithm
- Verify readiness and conditions: retrieve codes and freeze frame, warm engine to normal operating temperature, clear code and attempt to reproduce.
- Monitor live data: confirm Bank 2 Sensor 1 voltage stays low (
- Check fuel trims: large positive LTFT on Bank 2 supports a true lean condition; if trims are normal, suspect sensor/electrical fault.
- Inspect wiring/connectors: visually and physically check harness at the sensor for damage, corrosion, or heat chafe; repair any issues.
- Test sensor heater: with connector disconnected, measure heater resistance and check for supply voltage and PCM switching on power‑up; replace sensor if heater open or no voltage present from PCM when expected.
- Signal circuit test: backprobe signal wire and measure voltage; if the wire is held near ground, trace for short to chassis; disconnect sensor — if voltage jumps or behaves differently, suspect wiring or PCM.
- Check for mechanical causes of lean: perform smoke test for vacuum/exhaust leaks, inspect intake gasket/seal on Bank 2 side, and test fuel pressure and injector operation.
- Replace sensor only after confirming wiring and system conditions are good. After repair clear codes and road test through a full drive cycle to verify the code does not return.
Likely causes
- Failed or aging upstream O2 sensor on Bank 2
- Signal wire short to ground or chafed insulation at harness/connector
- Intake vacuum leak or exhaust leak on Bank 2 side causing a lean reading
- Low fuel pressure or restricted injector feeding Bank 2 cylinders
Fault status
Status
PCM detected the Bank 2 Sensor 1 oxygen sensor signal below the expected threshold for the required time or the sensor output is not switching as expected, indicating a low voltage (lean) signal or electrical fault in the sensor circuit.
Repair difficulty: Medium
Diagnostic time: 0.5-2.5 hours
Similar codes
Repair manuals
Manual library for LAND ROVER
320
Browse 320 LAND ROVER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.
LAND ROVER
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LAND ROVER: 2022
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Defender
- 90
- 90
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- 90 V8
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- 90 X
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- 90 X-Dynamic HSE
- 90 X-Dynamic HSE
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- 90 X-Dynamic S
- 90 X-Dynamic SE
- 90 X-Dynamic SE
- 110
- 110
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- 110 S
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- 110 V8
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- 110 V8 Carpathian Edition
- 110 V8 Carpathian Edition
- 110 X
- 110 X
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Discovery
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- R-Dynamic S, 2.0L Eng VIN X · 2.0L Eng VIN X2022: Discovery R-Dynamic S
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- R-Dynamic S, 3.0L Eng VIN U · 3.0L Eng VIN U2022: Discovery R-Dynamic S
- R-Dynamic S, 3.0L Eng VIN U · 3.0L Eng VIN U2022: Discovery R-Dynamic S
- S
- S
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Discovery Sport
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Range Rover
- Autobiography, 4.4L Eng VIN 7 · 4.4L Eng VIN 72022: Range Rover Autobiography
- Autobiography, 4.4L Eng VIN 7 · 4.4L Eng VIN 72022: Range Rover Autobiography
- Autobiography, 5.0L Eng VIN E · 5.0L Eng VIN E2022: Range Rover Autobiography
- Autobiography, 5.0L Eng VIN E · 5.0L Eng VIN E2022: Range Rover Autobiography
- 2022 Range Rover Base
- 2022 Range Rover Base
- First Edition
- First Edition
- HSE Westminster, 3.0L Eng VIN U · 3.0L Eng VIN U2022: Range Rover HSE Westminster
- HSE Westminster, 3.0L Eng VIN U · 3.0L Eng VIN U2022: Range Rover HSE Westminster
- HSE Westminster, 5.0L Eng VIN E · 5.0L Eng VIN E2022: Range Rover HSE Westminster
- HSE Westminster, 5.0L Eng VIN E · 5.0L Eng VIN E2022: Range Rover HSE Westminster
- SE, 3.0L Eng VIN U · 3.0L Eng VIN U2022: Range Rover SE
- SE, 3.0L Eng VIN U · 3.0L Eng VIN U2022: Range Rover SE
- SE, 4.4L Eng VIN 7 · 4.4L Eng VIN 72022: Range Rover SE
- SE, 4.4L Eng VIN 7 · 4.4L Eng VIN 72022: Range Rover SE
- SV
- SV
- SVAutobiography
- SVAutobiography
- SVAutobiography Dynamic
- SVAutobiography Dynamic
- SVAutobiography Dynamic Blk.
- SVAutobiography Dynamic Blk.
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Range Rover Evoque
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Range Rover Velar
- R-Dynamic HSE
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- R-Dynamic S, 2.0L Eng VIN X · 2.0L Eng VIN X2022: Range Rover Velar R-Dynamic S
- R-Dynamic S, 2.0L Eng VIN X · 2.0L Eng VIN X2022: Range Rover Velar R-Dynamic S
- R-Dynamic S, 3.0L Eng VIN U · 3.0L Eng VIN U2022: Range Rover Velar R-Dynamic S
- R-Dynamic S, 3.0L Eng VIN U · 3.0L Eng VIN U2022: Range Rover Velar R-Dynamic S
- S, 2.0L Eng VIN X · 2.0L Eng VIN X2022: Range Rover Velar S
- S, 2.0L Eng VIN X · 2.0L Eng VIN X2022: Range Rover Velar S
- S, 3.0L Eng VIN U · 3.0L Eng VIN U2022: Range Rover Velar S
- S, 3.0L Eng VIN U · 3.0L Eng VIN U2022: Range Rover Velar S
-
-
LAND ROVER: 2021
-
Discovery
- R-Dynamic HSE
- R-Dynamic HSE
- R-Dynamic S, 2.0L Eng VIN X · 2.0L Eng VIN X2021: Discovery R-Dynamic S
- R-Dynamic S, 2.0L Eng VIN X · 2.0L Eng VIN X2021: Discovery R-Dynamic S
- R-Dynamic S, 3.0L Eng VIN U · 3.0L Eng VIN U2021: Discovery R-Dynamic S
- R-Dynamic S, 3.0L Eng VIN U · 3.0L Eng VIN U2021: Discovery R-Dynamic S
- S
- S
-
Discovery Sport
-
Range Rover
- Autobiography, 2.0L Eng VIN Y · 2.0L Eng VIN Y2021: Range Rover Autobiography
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- Autobiography Fifty Edition
- Autobiography Fifty Edition
- 2021 Range Rover Base
- 2021 Range Rover Base
- HSE, 2.0L Eng VIN Y · 2.0L Eng VIN Y2021: Range Rover HSE
- HSE, 2.0L Eng VIN Y · 2.0L Eng VIN Y2021: Range Rover HSE
- HSE, 3.0L Eng VIN K · 3.0L Eng VIN K2021: Range Rover HSE
- HSE, 3.0L Eng VIN K · 3.0L Eng VIN K2021: Range Rover HSE
- HSE Westminster, 3.0L Eng VIN U · 3.0L Eng VIN U2021: Range Rover HSE Westminster
- HSE Westminster, 3.0L Eng VIN U · 3.0L Eng VIN U2021: Range Rover HSE Westminster
- HSE Westminster, 5.0L Eng VIN E · 5.0L Eng VIN E2021: Range Rover HSE Westminster
- HSE Westminster, 5.0L Eng VIN E · 5.0L Eng VIN E2021: Range Rover HSE Westminster
- SVAutobiography
- SVAutobiography
- SVAutobiography Dynamic
- SVAutobiography Dynamic
- SVAutobiography Dynamic Blk.
- SVAutobiography Dynamic Blk.
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Range Rover Evoque
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Range Rover Sport
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- Autobiography, 2.0L Eng VIN Y · 2.0L Eng VIN Y2021: Range Rover Sport Autobiography
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- Autobiography, 5.0L Eng VIN E · 5.0L Eng VIN E2021: Range Rover Sport Autobiography
- Autobiography Dynamic, 2.0L Eng VIN Y · 2.0L Eng VIN Y2021: Range Rover Sport Autobiography Dynamic
- Autobiography Dynamic, 2.0L Eng VIN Y · 2.0L Eng VIN Y2021: Range Rover Sport Autobiography Dynamic
- Autobiography Dynamic, 5.0L Eng VIN E · 5.0L Eng VIN E2021: Range Rover Sport Autobiography Dynamic
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- HSE Dynamic
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- HSE Silver Edition, 2.0L Eng VIN Y · 2.0L Eng VIN Y2021: Range Rover Sport HSE Silver Edition
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- HSE Silver Edition, 3.0L Eng VIN K · 3.0L Eng VIN K2021: Range Rover Sport HSE Silver Edition
- HSE Silver Edition, 3.0L Eng VIN K · 3.0L Eng VIN K2021: Range Rover Sport HSE Silver Edition
- HSE Silver Edition, 3.0L Eng VIN U · 3.0L Eng VIN U2021: Range Rover Sport HSE Silver Edition
- HSE Silver Edition, 3.0L Eng VIN U · 3.0L Eng VIN U2021: Range Rover Sport HSE Silver Edition
- HST
- HST
- SE
- SE
- SVR
- SVR
- SVR Carbon Edition
- SVR Carbon Edition
-
Range Rover Velar
- R-Dynamic HSE
- R-Dynamic HSE
- R-Dynamic S, 2.0L Eng VIN X · 2.0L Eng VIN X2021: Range Rover Velar R-Dynamic S
- R-Dynamic S, 2.0L Eng VIN X · 2.0L Eng VIN X2021: Range Rover Velar R-Dynamic S
- R-Dynamic S, 3.0L Eng VIN U · 3.0L Eng VIN U2021: Range Rover Velar R-Dynamic S
- R-Dynamic S, 3.0L Eng VIN U · 3.0L Eng VIN U2021: Range Rover Velar R-Dynamic S
- S, 2.0L Eng VIN X · 2.0L Eng VIN X2021: Range Rover Velar S
- S, 2.0L Eng VIN X · 2.0L Eng VIN X2021: Range Rover Velar S
- S, 3.0L Eng VIN U · 3.0L Eng VIN U2021: Range Rover Velar S
- S, 3.0L Eng VIN U · 3.0L Eng VIN U2021: Range Rover Velar S
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LAND ROVER: 2020
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Defender
- 90 First Edition
- 90 First Edition
- 110 First Edition
- 110 First Edition
- 110 HSE
- 110 HSE
- 110 S
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- 110 SE
- 110 SE
- 110 X
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- 110, 2.0L Eng VIN X · 2.0L Eng VIN X2020: Defender 110
- 110, 2.0L Eng VIN X · 2.0L Eng VIN X2020: Defender 110
- 110, 3.0L Eng VIN U · 3.0L Eng VIN U2020: Defender 110
- 110, 3.0L Eng VIN U · 3.0L Eng VIN U2020: Defender 110
-
Discovery
- HSE, 3.0L Eng VIN K · 3.0L Eng VIN K2020: Discovery HSE
- HSE, 3.0L Eng VIN K · 3.0L Eng VIN K2020: Discovery HSE
- HSE, 3.0L Eng VIN V · 3.0L Eng VIN V2020: Discovery HSE
- HSE, 3.0L Eng VIN V · 3.0L Eng VIN V2020: Discovery HSE
- HSE Luxury, 3.0L Eng VIN K · 3.0L Eng VIN K2020: Discovery HSE Luxury
- HSE Luxury, 3.0L Eng VIN K · 3.0L Eng VIN K2020: Discovery HSE Luxury
- HSE Luxury, 3.0L Eng VIN V · 3.0L Eng VIN V2020: Discovery HSE Luxury
- HSE Luxury, 3.0L Eng VIN V · 3.0L Eng VIN V2020: Discovery HSE Luxury
- Landmark
- Landmark
- SE, 3.0L Eng VIN K · 3.0L Eng VIN K2020: Discovery SE
- SE, 3.0L Eng VIN K · 3.0L Eng VIN K2020: Discovery SE
- SE, 3.0L Eng VIN V · 3.0L Eng VIN V2020: Discovery SE
- SE, 3.0L Eng VIN V · 3.0L Eng VIN V2020: Discovery SE
-
Range Rover
- Autobiography
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- Base, 3.0L Eng VIN K · 3.0L Eng VIN K2020: Range Rover Base
- Base, 3.0L Eng VIN K · 3.0L Eng VIN K2020: Range Rover Base
- Base, 3.0L Eng VIN U · 3.0L Eng VIN U2020: Range Rover Base
- Base, 3.0L Eng VIN U · 3.0L Eng VIN U2020: Range Rover Base
- HSE, 2.0L Eng VIN Y · 2.0L Eng VIN Y2020: Range Rover HSE
- HSE, 2.0L Eng VIN Y · 2.0L Eng VIN Y2020: Range Rover HSE
- HSE, 3.0L Eng VIN K · 3.0L Eng VIN K2020: Range Rover HSE
- HSE, 3.0L Eng VIN K · 3.0L Eng VIN K2020: Range Rover HSE
- HSE, 3.0L Eng VIN U · 3.0L Eng VIN U2020: Range Rover HSE
- HSE, 3.0L Eng VIN U · 3.0L Eng VIN U2020: Range Rover HSE
- HSE, 5.0L Eng VIN E · 5.0L Eng VIN E2020: Range Rover HSE
- HSE, 5.0L Eng VIN E · 5.0L Eng VIN E2020: Range Rover HSE
- SVAutobiography
- SVAutobiography
- SVAutobiography Dynamic
- SVAutobiography Dynamic
-
Range Rover Evoque
-
Range Rover Sport
- Autobiography Dynamic, 2.0L Eng VIN Y · 2.0L Eng VIN Y2020: Range Rover Sport Autobiography Dynamic
- Autobiography Dynamic, 2.0L Eng VIN Y · 2.0L Eng VIN Y2020: Range Rover Sport Autobiography Dynamic
- Autobiography Dynamic, 5.0L Eng VIN E · 5.0L Eng VIN E2020: Range Rover Sport Autobiography Dynamic
- Autobiography Dynamic, 5.0L Eng VIN E · 5.0L Eng VIN E2020: Range Rover Sport Autobiography Dynamic
- HSE, 3.0L Eng VIN K · 3.0L Eng VIN K2020: Range Rover Sport HSE
- HSE, 3.0L Eng VIN K · 3.0L Eng VIN K2020: Range Rover Sport HSE
- HSE, 3.0L Eng VIN U · 3.0L Eng VIN U2020: Range Rover Sport HSE
- HSE, 3.0L Eng VIN U · 3.0L Eng VIN U2020: Range Rover Sport HSE
- HSE, 5.0L Eng VIN E · 5.0L Eng VIN E2020: Range Rover Sport HSE
- HSE, 5.0L Eng VIN E · 5.0L Eng VIN E2020: Range Rover Sport HSE
- HSE Dynamic
- HSE Dynamic
- HSE PHEV
- HSE PHEV
- HST
- HST
- SE, 3.0L Eng VIN K · 3.0L Eng VIN K2020: Range Rover Sport SE
- SE, 3.0L Eng VIN K · 3.0L Eng VIN K2020: Range Rover Sport SE
- SE, 3.0L Eng VIN U · 3.0L Eng VIN U2020: Range Rover Sport SE
- SE, 3.0L Eng VIN U · 3.0L Eng VIN U2020: Range Rover Sport SE
- SVR
- SVR
-
Range Rover Velar
- R-Dynamic HSE
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Code
P0151
MITSUBISHI
P — Powertrain
Oxygen sensor2(front) low
AI status
Completed
Completed
100%
Causes
- Faulty Bank 2 Sensor 1 (upstream O2 sensor)
- Wiring shorted to ground on the sensor signal circuit
- Open or corroded connector or poor sensor ground
- Exhaust leak upstream of the sensor
- Fuel delivery lean condition (low fuel pressure, clogged injector, intake leak)
- Sensor contamination (oil, coolant, silicone, sulfur)
Symptoms
- Check Engine Light (MIL) illuminated
- Poor fuel economy
- Rough idle or hesitation under load
- Difficulty passing emissions test
- Persistent lean fuel trims (positive long‑term fuel trim)
What to check
- Read and record all stored DTCs and freeze‑frame data
- Monitor live data: Bank 2 Sensor 1 voltage, heater status, short‑term and long‑term fuel trims
- Verify engine is at normal operating temperature before testing (sensor must be hot)
- Check for related codes (fuel trim, misfire, fuel pressure)
- Visually inspect sensor, connector and wiring for damage, corrosion, heat damage, or rubbing
- Perform a smoke test for vacuum/exhaust leaks on Bank 2 side
Signal parameters
- Expected zirconia O2 sensor voltage: approximately 0.1–0.9 V (lean ≈0.1–0.3 V, rich ≈0.6–0.9 V)
- Normal upstream switching: frequent transition between low and high as closed‑loop control operates
- P0151 symptom: persistent low/stuck voltage (near 0.1–0.2 V) or no switching
- Heater circuit: battery voltage applied with PCM control when key on/engine off; typical heater resistance often 2–20 Ω depending on sensor type (refer to vehicle spec)
Diagnostic algorithm
- Verify readiness and conditions: retrieve codes and freeze frame, warm engine to normal operating temperature, clear code and attempt to reproduce.
- Monitor live data: confirm Bank 2 Sensor 1 voltage stays low (
- Check fuel trims: large positive LTFT on Bank 2 supports a true lean condition; if trims are normal, suspect sensor/electrical fault.
- Inspect wiring/connectors: visually and physically check harness at the sensor for damage, corrosion, or heat chafe; repair any issues.
- Test sensor heater: with connector disconnected, measure heater resistance and check for supply voltage and PCM switching on power‑up; replace sensor if heater open or no voltage present from PCM when expected.
- Signal circuit test: backprobe signal wire and measure voltage; if the wire is held near ground, trace for short to chassis; disconnect sensor — if voltage jumps or behaves differently, suspect wiring or PCM.
- Check for mechanical causes of lean: perform smoke test for vacuum/exhaust leaks, inspect intake gasket/seal on Bank 2 side, and test fuel pressure and injector operation.
- Replace sensor only after confirming wiring and system conditions are good. After repair clear codes and road test through a full drive cycle to verify the code does not return.
Likely causes
- Failed or aging upstream O2 sensor on Bank 2
- Signal wire short to ground or chafed insulation at harness/connector
- Intake vacuum leak or exhaust leak on Bank 2 side causing a lean reading
- Low fuel pressure or restricted injector feeding Bank 2 cylinders
Fault status
Status
PCM detected the Bank 2 Sensor 1 oxygen sensor signal below the expected threshold for the required time or the sensor output is not switching as expected, indicating a low voltage (lean) signal or electrical fault in the sensor circuit.
Repair difficulty: Medium
Diagnostic time: 0.5-2.5 hours
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406
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