Fault code P0036 – a step-by-step guide to diagnosing and fixing it

Error code P0036 is displayed and the check engine light is on - what does this mean?

The OBD/EOBD system has detected a defect in the heating circuit of lambda sensor 2 in bank 1. This DTC P0036 specifically affects the heating of the downstream lambda sensor, which is responsible for monitoring the catalytic converter. With various manufacturers, this fault code can also be referred to as "O2 Sensor Heater Circuit High (Bank 1, Sensor 2)".

What causes can this error code have?

• Defective lambda sensor heater
• Damaged cable to the lambda sensor
• Corroded or loose plug connections
• Blown fuse in the heating circuit
• Defective engine control unit (ECU)
• Short circuit in the electrical wiring
• Overvoltage in the heating circuit
• Lambda sensor degradation due to ageing

Which symptoms occur in parallel with fault code P0036?

• Increased fuel consumption: The vehicle requires more fuel than usual because the mixture control is impaired.
• Poor exhaust values: Increased emission values are detected during the emissions test.
• Uneven engine running: The engine runs unevenly, especially when idling or at low engine speeds.
• Power loss: Noticeable reduction in engine power, especially at full throttle.
• Starting problems: The vehicle is harder to start, especially when the engine is cold.

How can the problem with error code P0036 be rectified?

• Repairing trouble code P0036 requires a systematic approach to identify the exact source of the fault.
• Replace the lambda sensor completely: Replace the downstream lambda sensor in bank 1, including the integrated heater, as these are usually installed as a unit (cost: 80-200 euros plus labor).
• Repair wiring and plug connections: Check and repair damaged cables, clean corroded contacts or replace defective connectors in the lambda sensor heating circuit.
• Replace the fuse in the heating circuit: Locate and replace the blown fuse for the lambda sensor heating circuit in the corresponding fuse box.
• Diagnose and repair the engine control unit: Professionally check the ECU for defects and repair or replace if necessary for internal faults.
• Check and correct the power supply: Measuring the vehicle electrical system voltage and rectifying overvoltage problems caused by a faulty alternator or voltage regulator.