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Home / DTC / P0036 — HO2S Heater Control Circuit Bank 1 Sensor 2

P0036 — HO2S Heater Control Circuit Bank 1 Sensor 2

Detailed page for trouble code P0036.

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Code

P0036

Generic P — Powertrain

HO2S Heater Control Circuit Bank 1 Sensor 2

Brand: Generic
Type: P — Powertrain
Views: UK: 35 EN: 72 RU: 86
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or short in heater supply or ground wiring
  • Blown fuse or faulty relay supplying the O2 heater
  • Failed downstream O2 sensor (heater element open or high resistance)
  • Poor connector contact or corrosion at sensor or ECM
  • Faulty ECM or driver transistor
  • Aftermarket sensor or incorrect replacement

Symptoms

  • Malfunction Indicator Lamp (MIL) illuminated
  • Possible failed emissions test
  • Reduced or altered catalyst monitoring readiness
  • Occasional rough idle or minor drivability changes (downstream sensor usually not used for fuel trim)
  • Possible poor fuel economy over time

What to check

  • Scan tool: read DTCs and freeze frame, confirm P0036 is current
  • Visually inspect sensor wiring and connector for damage, corrosion, or melting
  • Check fuse(s) and relay(s) related to O2 sensor heater circuit
  • Backprobe sensor heater connector with key ON to confirm supply voltage (~12 V)
  • Unplug sensor and measure heater resistance with multimeter
  • Inspect and wiggle harness while monitoring for intermittent faults

Signal parameters

  • Heater supply voltage (key ON): ~11–13.5 V at the sensor supply pin
  • Heater element resistance (typical): roughly 2–20 ohms (varies by sensor; consult vehicle spec)
  • Heater current when energized: typically ~0.5–3 A (varies by sensor)
  • ECM heater control: ground switched or PWM driver; when commanded ON the control pin should be pulled toward ground
  • No voltage or open circuit at heater pins indicates open circuit; near-battery voltage on both pins indicates short to battery

Diagnostic algorithm

  1. Verify the code with a scan tool, note freeze-frame and any related codes (engine misfire, CAN issues, other O2 faults).
  2. Perform a visual inspection of Bank 1 Sensor 2 wiring and connector (heat damage, chafing, corrosion). Repair as needed.
  3. Check relevant fuses and relays for the sensor heater circuit; replace if blown or faulty.
  4. With ignition ON (engine OFF), backprobe the sensor connector: verify battery voltage at the heater supply pin.
  5. With connector disconnected, measure heater element resistance between the heater pins. Compare to manufacturer spec; an open or very high resistance indicates a bad sensor.
  6. Command the heater ON via scan tool (if supported) and monitor voltage/current/ECM control pin. Verify the ECM toggles ground or PWM and that the heater draws expected current.
  7. Check for shorts: measure resistance from heater control pin to battery positive (short to B+) and to chassis ground (short to ground).
  8. Wiggle harness and connectors while observing live data or continuity to locate intermittent faults.
  9. If wiring and fuse/relay are good and sensor heater is out of spec, replace the downstream O2 sensor (Bank 1 Sensor 2).
  10. If new sensor does not clear code or heater control is not being switched by the ECM, inspect/troubleshoot ECM driver circuit or consider ECM replacement after verifying all other components.

Likely causes

  • Broken or disconnected heater wire at sensor harness
  • Corroded/loose sensor connector causing intermittent supply/ground
  • Blown heater fuse or failed relay in heater supply circuit
  • Internal heater element failure in the oxygen sensor
  • Short to battery or short to ground in the harness
  • ECM driver fault (less common)

Fault status

⚠️ Status
Heated oxygen sensor (HO2S) heater circuit malfunction detected for Bank 1 Sensor 2 — check heater element, wiring, fuse/relay, and ECM control.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.0 hours

Similar codes

P0035 P0037 P0038 P0136 P0141 P0156
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Code

P0036

HUMMER P — Powertrain

Heated Oxygen Sensor (HO2S) Heater Control Circuit Bank 1 Sensor 2

Brand: HUMMER
Type: P — Powertrain
Views: UK: 22 EN: 45 RU: 59
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or short in heater supply or ground wiring
  • Blown fuse or faulty relay supplying the O2 heater
  • Failed downstream O2 sensor (heater element open or high resistance)
  • Poor connector contact or corrosion at sensor or ECM
  • Faulty ECM or driver transistor
  • Aftermarket sensor or incorrect replacement

Symptoms

  • Malfunction Indicator Lamp (MIL) illuminated
  • Possible failed emissions test
  • Reduced or altered catalyst monitoring readiness
  • Occasional rough idle or minor drivability changes (downstream sensor usually not used for fuel trim)
  • Possible poor fuel economy over time

What to check

  • Scan tool: read DTCs and freeze frame, confirm P0036 is current
  • Visually inspect sensor wiring and connector for damage, corrosion, or melting
  • Check fuse(s) and relay(s) related to O2 sensor heater circuit
  • Backprobe sensor heater connector with key ON to confirm supply voltage (~12 V)
  • Unplug sensor and measure heater resistance with multimeter
  • Inspect and wiggle harness while monitoring for intermittent faults

Signal parameters

  • Heater supply voltage (key ON): ~11–13.5 V at the sensor supply pin
  • Heater element resistance (typical): roughly 2–20 ohms (varies by sensor; consult vehicle spec)
  • Heater current when energized: typically ~0.5–3 A (varies by sensor)
  • ECM heater control: ground switched or PWM driver; when commanded ON the control pin should be pulled toward ground
  • No voltage or open circuit at heater pins indicates open circuit; near-battery voltage on both pins indicates short to battery

Diagnostic algorithm

  1. Verify the code with a scan tool, note freeze-frame and any related codes (engine misfire, CAN issues, other O2 faults).
  2. Perform a visual inspection of Bank 1 Sensor 2 wiring and connector (heat damage, chafing, corrosion). Repair as needed.
  3. Check relevant fuses and relays for the sensor heater circuit; replace if blown or faulty.
  4. With ignition ON (engine OFF), backprobe the sensor connector: verify battery voltage at the heater supply pin.
  5. With connector disconnected, measure heater element resistance between the heater pins. Compare to manufacturer spec; an open or very high resistance indicates a bad sensor.
  6. Command the heater ON via scan tool (if supported) and monitor voltage/current/ECM control pin. Verify the ECM toggles ground or PWM and that the heater draws expected current.
  7. Check for shorts: measure resistance from heater control pin to battery positive (short to B+) and to chassis ground (short to ground).
  8. Wiggle harness and connectors while observing live data or continuity to locate intermittent faults.
  9. If wiring and fuse/relay are good and sensor heater is out of spec, replace the downstream O2 sensor (Bank 1 Sensor 2).
  10. If new sensor does not clear code or heater control is not being switched by the ECM, inspect/troubleshoot ECM driver circuit or consider ECM replacement after verifying all other components.

Likely causes

  • Broken or disconnected heater wire at sensor harness
  • Corroded/loose sensor connector causing intermittent supply/ground
  • Blown heater fuse or failed relay in heater supply circuit
  • Internal heater element failure in the oxygen sensor
  • Short to battery or short to ground in the harness
  • ECM driver fault (less common)

Fault status

⚠️ Status
Heated oxygen sensor (HO2S) heater circuit malfunction detected for Bank 1 Sensor 2 — check heater element, wiring, fuse/relay, and ECM control.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.0 hours

Similar codes

P0035 P0037 P0038 P0136 P0141 P0156
Repair manuals

Manual library for HUMMER

138

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Code

P0036

LAND ROVER P — Powertrain

Heated oxygen sensor heater control circuit (bank 1, sensor 2)

Brand: LAND ROVER
Type: P — Powertrain
Views: UK: 16 EN: 35 RU: 55
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or short in heater supply or ground wiring
  • Blown fuse or faulty relay supplying the O2 heater
  • Failed downstream O2 sensor (heater element open or high resistance)
  • Poor connector contact or corrosion at sensor or ECM
  • Faulty ECM or driver transistor
  • Aftermarket sensor or incorrect replacement

Symptoms

  • Malfunction Indicator Lamp (MIL) illuminated
  • Possible failed emissions test
  • Reduced or altered catalyst monitoring readiness
  • Occasional rough idle or minor drivability changes (downstream sensor usually not used for fuel trim)
  • Possible poor fuel economy over time

What to check

  • Scan tool: read DTCs and freeze frame, confirm P0036 is current
  • Visually inspect sensor wiring and connector for damage, corrosion, or melting
  • Check fuse(s) and relay(s) related to O2 sensor heater circuit
  • Backprobe sensor heater connector with key ON to confirm supply voltage (~12 V)
  • Unplug sensor and measure heater resistance with multimeter
  • Inspect and wiggle harness while monitoring for intermittent faults

Signal parameters

  • Heater supply voltage (key ON): ~11–13.5 V at the sensor supply pin
  • Heater element resistance (typical): roughly 2–20 ohms (varies by sensor; consult vehicle spec)
  • Heater current when energized: typically ~0.5–3 A (varies by sensor)
  • ECM heater control: ground switched or PWM driver; when commanded ON the control pin should be pulled toward ground
  • No voltage or open circuit at heater pins indicates open circuit; near-battery voltage on both pins indicates short to battery

Diagnostic algorithm

  1. Verify the code with a scan tool, note freeze-frame and any related codes (engine misfire, CAN issues, other O2 faults).
  2. Perform a visual inspection of Bank 1 Sensor 2 wiring and connector (heat damage, chafing, corrosion). Repair as needed.
  3. Check relevant fuses and relays for the sensor heater circuit; replace if blown or faulty.
  4. With ignition ON (engine OFF), backprobe the sensor connector: verify battery voltage at the heater supply pin.
  5. With connector disconnected, measure heater element resistance between the heater pins. Compare to manufacturer spec; an open or very high resistance indicates a bad sensor.
  6. Command the heater ON via scan tool (if supported) and monitor voltage/current/ECM control pin. Verify the ECM toggles ground or PWM and that the heater draws expected current.
  7. Check for shorts: measure resistance from heater control pin to battery positive (short to B+) and to chassis ground (short to ground).
  8. Wiggle harness and connectors while observing live data or continuity to locate intermittent faults.
  9. If wiring and fuse/relay are good and sensor heater is out of spec, replace the downstream O2 sensor (Bank 1 Sensor 2).
  10. If new sensor does not clear code or heater control is not being switched by the ECM, inspect/troubleshoot ECM driver circuit or consider ECM replacement after verifying all other components.

Likely causes

  • Broken or disconnected heater wire at sensor harness
  • Corroded/loose sensor connector causing intermittent supply/ground
  • Blown heater fuse or failed relay in heater supply circuit
  • Internal heater element failure in the oxygen sensor
  • Short to battery or short to ground in the harness
  • ECM driver fault (less common)

Fault status

⚠️ Status
Heated oxygen sensor (HO2S) heater circuit malfunction detected for Bank 1 Sensor 2 — check heater element, wiring, fuse/relay, and ECM control.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.0 hours

Similar codes

P0035 P0037 P0038 P0136 P0141 P0156
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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+100 karma for a short comment :)
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