Diagnostic Trouble Code
P0135 — O2 Sensor Heater Circuit Malfunction — Bank 1 Sensor 1
O2 Sensor Heater Circuit Malfunction — Bank 1 Sensor 1
Definition
The ECM has detected a malfunction in the heater circuit of the upstream oxygen sensor on Bank 1. The heater brings the O2 sensor to operating temperature quickly, enabling closed-loop fuel control sooner after cold start.
Common Causes
- Failed O2 sensor heater element
- Blown fuse for the O2 sensor heater circuit
- Damaged wiring between the ECM and O2 sensor
- Corroded O2 sensor connector