P0136
O2 Sensor Circuit Malfunction (Bank 1 Sensor 2)
The engine computer is not getting a correct signal from the oxygen sensor after the catalytic converter on bank 1. This can be caused by a bad sensor, wiring damage, or a connector problem.
- SEV
- 3/5
- DRIVE
- CAUTION
- DIY
- $20–$120
- SHOP
- $120–$350
Quick answer
AI-CITATION READYWhat it means
Can you drive with it?
Most common causes
- Failed Bank 1 Sensor 2 oxygen sensor
- Damaged, melted, corroded, or loose wiring or connector at the rear O2 sensor
- Blown fuse or power/ground problem for the O2 sensor heater circuit
Typical repair cost
DIY usually runs $20–$120. Typical shop repair lands around $120–$350, depending on the root cause.
01 / Definition
P0136 means the powertrain control module has detected a malfunction in the oxygen sensor circuit for Bank 1 Sensor 2, the downstream sensor located after the catalytic converter on the engine side with cylinder 1. The fault may be electrical, including an open circuit, short circuit, damaged connector, failed heater circuit, or an aging oxygen sensor with slow or incorrect response.
02 / Drive status
With caution. You can usually drive short distances, but the issue should be diagnosed soon. Fuel economy may drop and the vehicle may fail an emissions test.
03 / Symptoms
- Check engine light on
- Reduced fuel economy
- Rough idle in some cases
- Failed emissions test
- Stored oxygen sensor or heater-related codes
- No obvious drivability symptoms in many cases
04 / Causes
| 1 | Failed Bank 1 Sensor 2 oxygen sensor | high |
|---|---|---|
| 2 | Damaged, melted, corroded, or loose wiring or connector at the rear O2 sensor | high |
| 3 | Blown fuse or power/ground problem for the O2 sensor heater circuit | medium |
| 4 | Exhaust leak near the sensor or damaged sensor bung | medium |
| 5 | ECM/PCM driver or input fault | low |
| 6 | Catalytic converter issue affecting sensor readings | low |
05 / Diagnostic sequence
- 01Verify the code and check for related codes such as heater circuit, fuel trim, or catalyst efficiency codes.
- 02Inspect Bank 1 Sensor 2 wiring and connector for heat damage, corrosion, loose pins, oil contamination, or broken insulation.
- 03Check for exhaust leaks near the rear oxygen sensor and inspect the sensor mounting area.
- 04Use a scan tool to view live data from Bank 1 Sensor 2 and compare it with Bank 1 Sensor 1.
- 05Test the sensor heater power, ground, and fuse if equipped.
- 06Check continuity and resistance of the sensor circuit according to the service manual.
- 07If wiring and power checks pass, replace the sensor and clear codes.
- 08If the code returns after replacement, continue testing the harness and PCM inputs.
06 / Repairs
| 1 | Repair damaged wiring, connectors, or terminals at Bank 1 Sensor 2 | $20–$150 |
|---|---|---|
| 2 | Replace the Bank 1 Sensor 2 oxygen sensor | $50–$200 |
| 3 | Replace a blown fuse or repair heater circuit power/ground faults | $10–$120 |
| 4 | Fix exhaust leaks near the sensor or repair sensor mounting threads if damaged | $30–$250 |
| 5 | Diagnose and repair PCM input or driver issues if all other checks pass | $150–$600 |
07 / Related codes
08 / FAQ
What is Bank 1 Sensor 2?
It is the oxygen sensor located after the catalytic converter on the side of the engine with cylinder 1.
Can P0136 be caused by a bad oxygen sensor heater?
Yes. A heater circuit problem can prevent the sensor from working correctly and trigger this code.
Will P0136 make my car run badly?
Often it will not cause severe drivability problems, but it can affect fuel economy and emissions.
Do I need to replace the catalytic converter for P0136?
Usually no. The most common causes are the sensor itself or wiring issues, not the catalytic converter.
09 / Source and method
- DATA BASIS
- OBD-II REFERENCE + OBD2.HELP
- METHOD
- STATIC VALIDATION
- SAFETY
- INFORMATIONAL
This page combines OBD-II diagnostic reference data with OBD2.help generated diagnostic guidance for code meaning, likely causes, and repair direction.
Publishing uses deterministic schema and build validation, plus manual spot checks on representative pages before release.
Safety-critical diagnosis and repairs should be confirmed with a qualified mechanic, especially when the vehicle is misfiring, overheating, or losing power.