What does it mean?
P1136 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: HO2S Heater Circuit Heater Resistance .
Symptoms
- Malfunction indicator lamp on shortly after start-up
- Slow warm-up of the sensor and a long open loop period
- Higher fuel consumption on short journeys
- Idle quality slightly poor until the engine is fully warm
- Emissions readiness monitors staying incomplete
Likely causes
- Heater element resistance drifted upward as the ceramic and winding aged
- Cracked element caused by moisture in the exhaust hitting a hot sensor on short trips
- Non-specification replacement sensor with a different heater rating
- Corrosion inside the connector adding resistance in series with the element
- Partially melted or pinched heater wire creating a high resistance joint
- Poor heater ground connection at the body or at the module
- Very low system voltage skewing the resistance calculation the controller performs
How to fix it
- Measure the cold resistance across the heater pins and compare it with the value specified for that sensor
- Repeat the measurement while gently flexing the pigtail to expose an intermittent high resistance
- Inspect connector terminals for corrosion, then clean and retension them before retesting
- Check heater supply voltage and the ground side voltage drop with the heater energised
- Confirm the fitted sensor is the correct part for that position and not a generic universal unit
- Check charging system voltage, since low battery voltage can distort the monitor result
- Replace the sensor if resistance stays out of specification, then confirm the heater monitor passes on a new drive cycle