EngineLightCodes
Powertrain code

P0136 O2 Sensor Circuit Bank 1 Sensor 2

Severity
Fix soon
Typical repair cost
$70–$280
Do it yourself
Possible, easy
Shop time
0.3–1.5 hours

The oxygen sensor after the catalytic converter on bank 1 (sensor 2) is a switching sensor (about 0.1–0.9 V) used for converter monitoring and fine mixture trim.

How the engine computer detects it

P0136 is the general circuit code, and its exact meaning varies by manufacturer. Ford sets it as 'no activity' in a functional check: if the sensor never swings beyond about 0.42/0.48 V despite rich and lean phases – if needed after forced enrichment and leaning – once per drive cycle. Opel/GM Europe set it if the average voltage stays outside 400–500 mV after 10 min of closed loop; older Bosch Motronic if it stays at 0 V for 200 s despite heating. GM North America does not use P0136. When it fails, the control module stops the downstream trim and cannot evaluate the converter; there is no limp mode.

Written from public technical sources and not yet checked by a mechanic. How we write these pages

Symptoms

  • Check engine light on (usually after two drive cycles)
  • Catalyst monitor readiness not set
  • Slightly higher consumption possible without downstream trim

Common causes

  1. Downstream sensor aged or poisoned (stays in the middle band) Most likely
  2. Signal or ground wire open or high-resistance, connector corroded Possible
  3. Sensor heater failed (sensor stays cold) Possible
  4. Exhaust leak ahead of the sensor Less likely
  5. Control module or software Less likely

How to diagnose P0136

  1. Read every stored code with an OBD-II scanner. If misfire or fuel trim codes are there too, fix those first: they often cause this one.
  2. Inspect the parts involved: oxygen sensor bank1 sensor2, oxygen sensor wiring, catalytic converter.
  3. Work through the causes above from most to least likely, cheapest checks first.
  4. Clear the code and drive a full drive cycle to confirm the repair held.

Reading the code

P
Powertrain
0
Generic (SAE) code
1
Fuel and air metering
36
Specific fault

Questions drivers ask

Can I drive with code P0136?

Usually yes for a short time, if the car drives normally, the temperature gauge reads normal and the check engine light is steady. If the light flashes, the engine loses power or overheats, or other warning lights come on, pull over and have it checked.

Will my car pass an emissions inspection with P0136?

Probably not in states that test vehicles with an OBD-II scan: an emissions-related code that keeps the check engine light on is usually an automatic fail. Rules differ by state and county, so check yours.

Will P0136 clear by itself?

The light can go off after several drive cycles without the fault, but the code returns if the cause is still there. After a repair, the readiness monitors need a full drive cycle before an inspection.

Can I fix P0136 myself?

Often yes, with an OBD-II scanner and basic tools. Difficulty: easy. Start with the cheapest checks before replacing expensive parts.

This page is general information, not a substitute for a professional diagnosis. Repair costs are rough estimates for parts and labor and vary by vehicle and region.