Error code

OBD2 P0135

OBD2P0135
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

O2 Sensor Heater Circuit.

Severity

moderateCan drive, but may fail emissions testing.

Summary

P0135 indicates a malfunction in the heater circuit of the oxygen sensor (HO2S) on bank 1, which is typically located ahead of the catalytic converter.

Symptoms

  • Illuminated check engine light
  • Potential failure during emissions testing

Common Causes

  • Problem on the ground side of the O2 sensor heater circuit
  • Problem on the power side of the O2 sensor heater circuit
  • High resistance in the O2 sensor heater element
  • Open circuit in the O2 sensor heater element

Diagnosis

  1. Test the heater circuit wiring for power and ground using a multimeter.
  2. Check the resistance of the sensor heating element to determine if it has high resistance or an open circuit.

Fixes

  • Replace faulty O2 sensor

FAQ

What does P0135 mean?

P0135 indicates a malfunction in the heater circuit of the oxygen sensor on bank 1.

How do I diagnose P0135?

Diagnose by testing the power and ground connections to the O2 sensor's heater circuit, and checking for high resistance or an open circuit in the heating element.

View source

Not affiliated with OBD2. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.

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