P0136 Oxygen sensor circuit (bank 1, sensor 2)
What P0136 means
The engine computer has found a problem with the signal from the downstream oxygen sensor on bank 1, the sensor after the catalytic converter. This sensor mainly checks how well the converter works, so the fault usually affects emissions monitoring more than how the car drives.
P0136 is a generic SAE J2012 code: it means the same on every make. The exact cause still depends on the car, so read the freeze-frame data before replacing parts.
At a glance
- Severity
- Medium
- Typical repair cost
- 60–300 €
- Workshop time
- 0.3–1.5 h
- Repair difficulty
- Easy
- DIY possible
- Yes
- Check engine light
- Yes
- Affects emissions test
- Yes
Parts and labour at an independent workshop in Europe. Main dealers charge more; the cause decides the bill, not the code.
Symptoms
- Check engine light on
- Usually no noticeable change in how the car drives
- Catalyst readiness monitor not completing
- Possible failed emissions test at inspection
Common causes
- Aged or contaminated downstream oxygen sensor
- Damaged wiring or corroded connector under the car
- Signal wire shorted to ground or voltage
- Exhaust leak near the sensor
Can I keep driving with P0136?
You can keep driving, but have it checked within one to two weeks. The engine is rarely affected, but the catalyst check cannot run and the car may fail its emissions inspection.
What to check first
- Inspect the downstream sensor wiring and connector for damage from heat, road debris and corrosion.
- Check the exhaust around the sensor for leaks.
- Watch the live sensor signal on a warm engine; it should hold a fairly steady value rather than drop to zero or stick at maximum.
- Replace the sensor if the wiring is good and the signal is implausible.
Related codes
- P0135 Oxygen sensor heater circuit (bank 1, sensor 1)
- P0137 Oxygen sensor circuit low voltage (bank 1, sensor 2)
- P0134 Oxygen sensor circuit no activity detected (bank 1, sensor 1)
- P0138 Oxygen sensor circuit high voltage (bank 1, sensor 2)
- P0133 Oxygen sensor slow response (bank 1 sensor 1)
- P0139 Oxygen sensor circuit slow response (bank 1, sensor 2)
- P0132 Oxygen sensor circuit high voltage (bank 1, sensor 1)
- P0131 Oxygen sensor circuit low voltage (bank 1, sensor 1)
Data: TORKO fault-code catalogue, built on OBDex (CC0-1.0) and reviewed against workshop practice. Informational only — it does not replace a diagnosis by a mechanic.
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