P1105moderate severityPowertrain
HO2S Heater Resistance Bank 1 Sensor 2
on 1999 Audi A3 1.6L I4 · FWD
What this code means
The ECU detected that the heater resistance in the downstream oxygen sensor on Bank 1 is outside the expected range. The downstream sensor monitors catalytic converter efficiency and requires proper heater function.
Symptoms
- Check Engine Light
- Failed emissions test
- Poor catalyst monitoring
- Slightly reduced fuel economy
Common causes
- Faulty downstream O2 sensor heater
- High resistance in heater wiring
- Corroded connector at sensor
- Heater relay failure
Diagnostic steps
- Test downstream O2 sensor heater resistance
- Inspect connector for corrosion
- Check heater circuit wiring
- Test heater relay operation
Repair notes
Replace the downstream O2 sensor on Bank 1.
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