OBD Guide

P0155

O2 Sensor Heater Circuit Bank 2 Sensor 1

Severity: MEDIUM

Symptoms

  • Increased fuel consumption
  • Unstable engine operation at idle
  • Reduced engine power
  • Check Engine Light Illuminates

Causes

  • Open or short circuit in the sensor heating circuit
  • Malfunction of the oxygen sensor itself
  • Problems in the wiring harness or connectors
  • Faulty heating circuit relay or fuse
  • Problems with the engine control unit (ECU)

How to Fix

  1. Check the integrity of the sensor heating circuit (resistance and voltage)
  2. Inspect the wiring harness and connectors for damage.
  3. Check the fuse and relay of the heating circuit
  4. If necessary, replace the oxygen sensor
  5. Clear error memory and check if code is returned

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