P0135low severityPowertrain
O2 Sensor Heater Circuit Bank 1 Sensor 1
on 2005-2011 Audi A6 4.2L V8 · AWD
What this code means
The PCM detected a malfunction in the heater element of the upstream O2 sensor on Bank 1.
Symptoms
- Check Engine Light
- Extended warmup emissions
- Failed emissions test
Common causes
- Faulty O2 sensor heater element
- Blown fuse
- Wiring damage
- PCM heater driver failure
Diagnostic steps
- Check O2 heater fuse
- Test heater resistance (typically 2-30 ohms)
- Inspect wiring
- Check PCM heater relay output
Repair notes
Replace O2 sensor if heater resistance is open or out of spec.
Other Powertrain codes on this vehicle
P0001
Fuel Volume Regulator Control Circuit/Open
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0003
Fuel Volume Regulator Control Circuit Low
P0004
Fuel Volume Regulator Control Circuit High
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1
P0011
Intake Camshaft Position Timing Over-Advanced Bank 1
P0012
Intake Camshaft Position Timing Over-Retarded Bank 1
P0013
Exhaust Camshaft Position Actuator Circuit/Open Bank 1
P0014
Exhaust Camshaft Position Timing Over-Advanced Bank 1
P0015
Exhaust Camshaft Position Timing Over-Retarded Bank 1