P0135
O2 Heater Circuit Malfunction (Bank 1 Sensor 1)
System: Emissions
Severity: medium
What does P0135 mean?
The DTC P0135 (O2 Heater Circuit Malfunction (Bank 1 Sensor 1)) is a fault code stored by the ECU when it detects a O2 heater B1S1 condition in the emissions subsystem. It is commonly seen on European and Asian vehicles using Bosch, Continental, Siemens or Denso ECUs.
Common causes of P0135
- Failed sensor heater element
- Heater fuse blown
- Wiring fault
- ECU heater driver
How to fix P0135
Check heater fuse. Measure heater resistance — replace sensor if open. Cheap fix usually.
Tuning approach with DaVinci Deluxe
For P0135, DaVinci Deluxe offers the following ECU map adjustments and software solutions:
- Heater monitor disable (race only)
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