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Home / DTC / P0155 — O2 Sensor Heater Circuit Bank 2 Sensor 1

P0155 — O2 Sensor Heater Circuit Bank 2 Sensor 1

Detailed page for trouble code P0155.

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Code

P0155

Generic P — Powertrain

O2 Sensor Heater Circuit Bank 2 Sensor 1

Brand: Generic
Type: P — Powertrain
Views: UK: 19 EN: 24 RU: 30
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or short in the heater wiring (broken wire, chafing to ground or power)
  • Bad oxygen (O2) sensor heater element (internal open or high resistance)
  • Corroded, loose, or damaged sensor connector or pins
  • Blown fuse or relay feeding the heater circuit
  • Poor ground or poor power supply to the heater circuit
  • PCM or control circuit fault (rare)

Symptoms

  • Check Engine Light (MIL) illuminated
  • Longer warm-up time for closed-loop fuel control; vehicle may run open-loop after cold start
  • Poor fuel economy or increased emissions
  • Rough idle or hesitation during cold start
  • Possible failed emissions test

What to check

  • Retrieve freeze frame and live data with a scan tool; confirm P0155 and note related codes
  • Visually inspect the Bank 2 Sensor 1 connector, wiring harness, and nearby components for damage, corrosion, or heat exposure
  • Check relevant fuses and relays for the oxygen sensor heater circuit
  • With key ON (engine OFF), check for battery voltage at the sensor's heater power terminal (if applicable) and a reference/ground at the heater ground terminal
  • Measure heater element resistance at the sensor (sensor removed) and compare to specification or typical range
  • Perform continuity test from sensor connector to PCM for power and ground/driver circuit; check for shorts to ground or battery

Signal parameters

  • Heater element resistance (typical range): ~2–20 ohms (varies by sensor — consult vehicle spec)
  • Heater supply voltage (key ON, engine OFF): approximately battery voltage (9–14 V) on the feed circuit when fused
  • Heater current when energized: commonly ~0.5–2 A depending on sensor design
  • PCM control: either on/off or PWM duty cycle to the heater; verify PCM commands heater on during warm-up

Diagnostic algorithm

  1. Confirm the code and check for related codes (other O2 sensor or heater DTCs). Note freeze-frame data.
  2. Perform a visual inspection of the Bank 2 Sensor 1 connector and wiring for corrosion, heat damage or rodent chewing. Repair visible damage.
  3. Verify fuses and relays for the heater circuit; replace if blown and re-test. If fuse blows again, suspect short to power/ground.
  4. With connector disconnected, measure heater resistance across the sensor heater terminals. If open or out of specified range, replace the sensor.
  5. With key ON (engine OFF), check for battery voltage at the heater power pin. If no power, trace supply fuse/relay and wiring back to source.
  6. Command the heater ON with a scan tool (if supported) and measure voltage/current at the connector while monitoring PCM command. If PCM commands but no current, suspect wiring or open heater.
  7. Check continuity from the sensor heater ground/driver circuit back to the PCM. Look for high resistance or short to voltage/ground.
  8. Repair or replace damaged wiring/connectors. If wiring checks good and heater element tests good, consider PCM driver fault and test or replace PCM per manufacturer procedures.
  9. After repairs, clear codes and perform a warm-up verification / test drive to confirm heater reaches operating condition and code does not return.

Likely causes

  • Damaged or corroded sensor connector at Bank 2 Sensor 1
  • Failed heater element in the oxygen sensor (common)
  • Open or shorted wire between sensor connector and PCM
  • Blown fuse supplying heater circuit or failed relay
  • High-resistance ground or poor PCM connector contact

Fault status

⚠️ Status
PCM reports a failure in the heater circuit for O2 Sensor Bank 2 Sensor 1 — heater open, short, or abnormal current draw detected; sensor may not reach operating temperature.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.0 hours
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Code

P0155

GWM P — Powertrain

- O2 sensor heating circuit fault (bank 2, sensor 1)

Brand: GWM
Type: P — Powertrain
Views: UK: 1 EN: 4 RU: 8
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or short in the heater wiring (broken wire, chafing to ground or power)
  • Bad oxygen (O2) sensor heater element (internal open or high resistance)
  • Corroded, loose, or damaged sensor connector or pins
  • Blown fuse or relay feeding the heater circuit
  • Poor ground or poor power supply to the heater circuit
  • PCM or control circuit fault (rare)

Symptoms

  • Check Engine Light (MIL) illuminated
  • Longer warm-up time for closed-loop fuel control; vehicle may run open-loop after cold start
  • Poor fuel economy or increased emissions
  • Rough idle or hesitation during cold start
  • Possible failed emissions test

What to check

  • Retrieve freeze frame and live data with a scan tool; confirm P0155 and note related codes
  • Visually inspect the Bank 2 Sensor 1 connector, wiring harness, and nearby components for damage, corrosion, or heat exposure
  • Check relevant fuses and relays for the oxygen sensor heater circuit
  • With key ON (engine OFF), check for battery voltage at the sensor's heater power terminal (if applicable) and a reference/ground at the heater ground terminal
  • Measure heater element resistance at the sensor (sensor removed) and compare to specification or typical range
  • Perform continuity test from sensor connector to PCM for power and ground/driver circuit; check for shorts to ground or battery

Signal parameters

  • Heater element resistance (typical range): ~2–20 ohms (varies by sensor — consult vehicle spec)
  • Heater supply voltage (key ON, engine OFF): approximately battery voltage (9–14 V) on the feed circuit when fused
  • Heater current when energized: commonly ~0.5–2 A depending on sensor design
  • PCM control: either on/off or PWM duty cycle to the heater; verify PCM commands heater on during warm-up

Diagnostic algorithm

  1. Confirm the code and check for related codes (other O2 sensor or heater DTCs). Note freeze-frame data.
  2. Perform a visual inspection of the Bank 2 Sensor 1 connector and wiring for corrosion, heat damage or rodent chewing. Repair visible damage.
  3. Verify fuses and relays for the heater circuit; replace if blown and re-test. If fuse blows again, suspect short to power/ground.
  4. With connector disconnected, measure heater resistance across the sensor heater terminals. If open or out of specified range, replace the sensor.
  5. With key ON (engine OFF), check for battery voltage at the heater power pin. If no power, trace supply fuse/relay and wiring back to source.
  6. Command the heater ON with a scan tool (if supported) and measure voltage/current at the connector while monitoring PCM command. If PCM commands but no current, suspect wiring or open heater.
  7. Check continuity from the sensor heater ground/driver circuit back to the PCM. Look for high resistance or short to voltage/ground.
  8. Repair or replace damaged wiring/connectors. If wiring checks good and heater element tests good, consider PCM driver fault and test or replace PCM per manufacturer procedures.
  9. After repairs, clear codes and perform a warm-up verification / test drive to confirm heater reaches operating condition and code does not return.

Likely causes

  • Damaged or corroded sensor connector at Bank 2 Sensor 1
  • Failed heater element in the oxygen sensor (common)
  • Open or shorted wire between sensor connector and PCM
  • Blown fuse supplying heater circuit or failed relay
  • High-resistance ground or poor PCM connector contact

Fault status

⚠️ Status
PCM reports a failure in the heater circuit for O2 Sensor Bank 2 Sensor 1 — heater open, short, or abnormal current draw detected; sensor may not reach operating temperature.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.0 hours
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Code

P0155

HUMMER P — Powertrain

Heated Oxygen Sensor (HO2S) Heater Performance Bank 2 Sensor 1

Brand: HUMMER
Type: P — Powertrain
Views: UK: 15 EN: 13 RU: 23
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or short in the heater wiring (broken wire, chafing to ground or power)
  • Bad oxygen (O2) sensor heater element (internal open or high resistance)
  • Corroded, loose, or damaged sensor connector or pins
  • Blown fuse or relay feeding the heater circuit
  • Poor ground or poor power supply to the heater circuit
  • PCM or control circuit fault (rare)

Symptoms

  • Check Engine Light (MIL) illuminated
  • Longer warm-up time for closed-loop fuel control; vehicle may run open-loop after cold start
  • Poor fuel economy or increased emissions
  • Rough idle or hesitation during cold start
  • Possible failed emissions test

What to check

  • Retrieve freeze frame and live data with a scan tool; confirm P0155 and note related codes
  • Visually inspect the Bank 2 Sensor 1 connector, wiring harness, and nearby components for damage, corrosion, or heat exposure
  • Check relevant fuses and relays for the oxygen sensor heater circuit
  • With key ON (engine OFF), check for battery voltage at the sensor's heater power terminal (if applicable) and a reference/ground at the heater ground terminal
  • Measure heater element resistance at the sensor (sensor removed) and compare to specification or typical range
  • Perform continuity test from sensor connector to PCM for power and ground/driver circuit; check for shorts to ground or battery

Signal parameters

  • Heater element resistance (typical range): ~2–20 ohms (varies by sensor — consult vehicle spec)
  • Heater supply voltage (key ON, engine OFF): approximately battery voltage (9–14 V) on the feed circuit when fused
  • Heater current when energized: commonly ~0.5–2 A depending on sensor design
  • PCM control: either on/off or PWM duty cycle to the heater; verify PCM commands heater on during warm-up

Diagnostic algorithm

  1. Confirm the code and check for related codes (other O2 sensor or heater DTCs). Note freeze-frame data.
  2. Perform a visual inspection of the Bank 2 Sensor 1 connector and wiring for corrosion, heat damage or rodent chewing. Repair visible damage.
  3. Verify fuses and relays for the heater circuit; replace if blown and re-test. If fuse blows again, suspect short to power/ground.
  4. With connector disconnected, measure heater resistance across the sensor heater terminals. If open or out of specified range, replace the sensor.
  5. With key ON (engine OFF), check for battery voltage at the heater power pin. If no power, trace supply fuse/relay and wiring back to source.
  6. Command the heater ON with a scan tool (if supported) and measure voltage/current at the connector while monitoring PCM command. If PCM commands but no current, suspect wiring or open heater.
  7. Check continuity from the sensor heater ground/driver circuit back to the PCM. Look for high resistance or short to voltage/ground.
  8. Repair or replace damaged wiring/connectors. If wiring checks good and heater element tests good, consider PCM driver fault and test or replace PCM per manufacturer procedures.
  9. After repairs, clear codes and perform a warm-up verification / test drive to confirm heater reaches operating condition and code does not return.

Likely causes

  • Damaged or corroded sensor connector at Bank 2 Sensor 1
  • Failed heater element in the oxygen sensor (common)
  • Open or shorted wire between sensor connector and PCM
  • Blown fuse supplying heater circuit or failed relay
  • High-resistance ground or poor PCM connector contact

Fault status

⚠️ Status
PCM reports a failure in the heater circuit for O2 Sensor Bank 2 Sensor 1 — heater open, short, or abnormal current draw detected; sensor may not reach operating temperature.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.0 hours
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Code

P0155

LAND ROVER P — Powertrain

malfunction in the heater circuit of the O2 sensor (bank 2 sensor 1)

Brand: LAND ROVER
Type: P — Powertrain
Views: UK: 5 EN: 8 RU: 16
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or short in the heater wiring (broken wire, chafing to ground or power)
  • Bad oxygen (O2) sensor heater element (internal open or high resistance)
  • Corroded, loose, or damaged sensor connector or pins
  • Blown fuse or relay feeding the heater circuit
  • Poor ground or poor power supply to the heater circuit
  • PCM or control circuit fault (rare)

Symptoms

  • Check Engine Light (MIL) illuminated
  • Longer warm-up time for closed-loop fuel control; vehicle may run open-loop after cold start
  • Poor fuel economy or increased emissions
  • Rough idle or hesitation during cold start
  • Possible failed emissions test

What to check

  • Retrieve freeze frame and live data with a scan tool; confirm P0155 and note related codes
  • Visually inspect the Bank 2 Sensor 1 connector, wiring harness, and nearby components for damage, corrosion, or heat exposure
  • Check relevant fuses and relays for the oxygen sensor heater circuit
  • With key ON (engine OFF), check for battery voltage at the sensor's heater power terminal (if applicable) and a reference/ground at the heater ground terminal
  • Measure heater element resistance at the sensor (sensor removed) and compare to specification or typical range
  • Perform continuity test from sensor connector to PCM for power and ground/driver circuit; check for shorts to ground or battery

Signal parameters

  • Heater element resistance (typical range): ~2–20 ohms (varies by sensor — consult vehicle spec)
  • Heater supply voltage (key ON, engine OFF): approximately battery voltage (9–14 V) on the feed circuit when fused
  • Heater current when energized: commonly ~0.5–2 A depending on sensor design
  • PCM control: either on/off or PWM duty cycle to the heater; verify PCM commands heater on during warm-up

Diagnostic algorithm

  1. Confirm the code and check for related codes (other O2 sensor or heater DTCs). Note freeze-frame data.
  2. Perform a visual inspection of the Bank 2 Sensor 1 connector and wiring for corrosion, heat damage or rodent chewing. Repair visible damage.
  3. Verify fuses and relays for the heater circuit; replace if blown and re-test. If fuse blows again, suspect short to power/ground.
  4. With connector disconnected, measure heater resistance across the sensor heater terminals. If open or out of specified range, replace the sensor.
  5. With key ON (engine OFF), check for battery voltage at the heater power pin. If no power, trace supply fuse/relay and wiring back to source.
  6. Command the heater ON with a scan tool (if supported) and measure voltage/current at the connector while monitoring PCM command. If PCM commands but no current, suspect wiring or open heater.
  7. Check continuity from the sensor heater ground/driver circuit back to the PCM. Look for high resistance or short to voltage/ground.
  8. Repair or replace damaged wiring/connectors. If wiring checks good and heater element tests good, consider PCM driver fault and test or replace PCM per manufacturer procedures.
  9. After repairs, clear codes and perform a warm-up verification / test drive to confirm heater reaches operating condition and code does not return.

Likely causes

  • Damaged or corroded sensor connector at Bank 2 Sensor 1
  • Failed heater element in the oxygen sensor (common)
  • Open or shorted wire between sensor connector and PCM
  • Blown fuse supplying heater circuit or failed relay
  • High-resistance ground or poor PCM connector contact

Fault status

⚠️ Status
PCM reports a failure in the heater circuit for O2 Sensor Bank 2 Sensor 1 — heater open, short, or abnormal current draw detected; sensor may not reach operating temperature.
🟡 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 Manual
Defender 300Tdi Years: 1996 Manual in English 7.5 MB
Short description

Official workshop manual for the Land Rover Defender 300Tdi (from 1996 model year). Contains specifications, adjustment, fault diagnosis and step-by-step repair and overhaul procedures for engine, transmission, axles, suspension, brakes, electrical and body. Intended for dealer workshops and trained technicians.

199,00 UAH
Contents
Key sections:
  • 01 INTRODUCTION
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  • 05 ENGINE TUNING DATA
  • 07 GENERAL FITTING REMINDERS
  • 09 LUBRICANTS, FLUIDS AND CAPACITIES
  • 10 MAINTENANCE
  • 12 ENGINE Tdi
  • - Description and operation
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  • - Adjustment
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Land Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)

Workshop Manual
Defender Years: 1999–2002 Manual in English 7.6 MB
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Workshop Manual Supplement and Body Repair Manual for the Land Rover Defender. Includes general specifications, maintenance schedules, tuning data and step‑by‑step repair procedures for engine, transmission, suspension, brakes, electrical and body repairs. Covers Defender models from 1999 and 2002 model years.

199,00 UAH
Contents
Key sections:
  • 01 - INTRODUCTION
  • - Introduction
  • - Dimensions
  • - References
  • - Repairs and replacements
  • - Poisonous substances
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  • - Synthetic rubber
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  • - Used engine oil precautions
  • - Accessories and conversions
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Land Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)

Workshop Manual
Manual in English Pages: 494 7.1 MB
Short description

Land Rover Range Rover Electrical Library (LRL 0453ENG). Comprehensive manual covering fuse details, earth points, system descriptions, diagnostics and connector pin-outs for electrical troubleshooting and repair. Intended for technicians and service workshops.

199,00 UAH
Contents
Key sections:
  • 1 INTRODUCTION
  • 1.1 About this document
  • 1.2 Battery voltage
  • 1.3 Electrical precautions
  • 1.4 Battery disconnecting / charging
  • 1.5 Disciplines / greases
  • 1.6 Abbreviations
  • 1.7 HeVAC, sensors abbreviations
  • 1.8 How to use this document
  • 1.9 Connector detail format
  • 1.10 Fault diagnosis
  • 1.11 Wire colour codes
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Code

P0155

MITSUBISHI P — Powertrain

Oxygen sensor2(front) heater

Brand: MITSUBISHI
Type: P — Powertrain
Views: UK: 11 EN: 11 RU: 22
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or short in the heater wiring (broken wire, chafing to ground or power)
  • Bad oxygen (O2) sensor heater element (internal open or high resistance)
  • Corroded, loose, or damaged sensor connector or pins
  • Blown fuse or relay feeding the heater circuit
  • Poor ground or poor power supply to the heater circuit
  • PCM or control circuit fault (rare)

Symptoms

  • Check Engine Light (MIL) illuminated
  • Longer warm-up time for closed-loop fuel control; vehicle may run open-loop after cold start
  • Poor fuel economy or increased emissions
  • Rough idle or hesitation during cold start
  • Possible failed emissions test

What to check

  • Retrieve freeze frame and live data with a scan tool; confirm P0155 and note related codes
  • Visually inspect the Bank 2 Sensor 1 connector, wiring harness, and nearby components for damage, corrosion, or heat exposure
  • Check relevant fuses and relays for the oxygen sensor heater circuit
  • With key ON (engine OFF), check for battery voltage at the sensor's heater power terminal (if applicable) and a reference/ground at the heater ground terminal
  • Measure heater element resistance at the sensor (sensor removed) and compare to specification or typical range
  • Perform continuity test from sensor connector to PCM for power and ground/driver circuit; check for shorts to ground or battery

Signal parameters

  • Heater element resistance (typical range): ~2–20 ohms (varies by sensor — consult vehicle spec)
  • Heater supply voltage (key ON, engine OFF): approximately battery voltage (9–14 V) on the feed circuit when fused
  • Heater current when energized: commonly ~0.5–2 A depending on sensor design
  • PCM control: either on/off or PWM duty cycle to the heater; verify PCM commands heater on during warm-up

Diagnostic algorithm

  1. Confirm the code and check for related codes (other O2 sensor or heater DTCs). Note freeze-frame data.
  2. Perform a visual inspection of the Bank 2 Sensor 1 connector and wiring for corrosion, heat damage or rodent chewing. Repair visible damage.
  3. Verify fuses and relays for the heater circuit; replace if blown and re-test. If fuse blows again, suspect short to power/ground.
  4. With connector disconnected, measure heater resistance across the sensor heater terminals. If open or out of specified range, replace the sensor.
  5. With key ON (engine OFF), check for battery voltage at the heater power pin. If no power, trace supply fuse/relay and wiring back to source.
  6. Command the heater ON with a scan tool (if supported) and measure voltage/current at the connector while monitoring PCM command. If PCM commands but no current, suspect wiring or open heater.
  7. Check continuity from the sensor heater ground/driver circuit back to the PCM. Look for high resistance or short to voltage/ground.
  8. Repair or replace damaged wiring/connectors. If wiring checks good and heater element tests good, consider PCM driver fault and test or replace PCM per manufacturer procedures.
  9. After repairs, clear codes and perform a warm-up verification / test drive to confirm heater reaches operating condition and code does not return.

Likely causes

  • Damaged or corroded sensor connector at Bank 2 Sensor 1
  • Failed heater element in the oxygen sensor (common)
  • Open or shorted wire between sensor connector and PCM
  • Blown fuse supplying heater circuit or failed relay
  • High-resistance ground or poor PCM connector contact

Fault status

⚠️ Status
PCM reports a failure in the heater circuit for O2 Sensor Bank 2 Sensor 1 — heater open, short, or abnormal current draw detected; sensor may not reach operating temperature.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.0 hours
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