B0103moderate severityBody
Immobilizer Antenna Ring Circuit
on 2011 Audi A4 2.0L Turbo I4 · AWD
What this code means
Malfunction in the immobilizer antenna ring (transponder receiver coil) around the ignition lock cylinder or start button.
Symptoms
- Intermittent no-start
- Security light on
- Key sometimes not recognized
- Works with key held in specific position
Common causes
- Faulty antenna ring coil
- Wiring damage from steering column work
- Connector loose
- Coil winding open or shorted
Diagnostic steps
- Measure antenna ring resistance
- Inspect connector at steering column
- Check wiring from antenna to immobilizer module
- Test with oscilloscope for signal
Repair notes
Replace immobilizer antenna ring. Ensure connector is fully seated after steering column work.
Other Body codes on this vehicle
B0001
Driver Frontal Stage 1 Deployment Control
B0002
Driver Frontal Stage 2 Deployment Control
B0003
Passenger Frontal Stage 1 Deployment Control
B0004
Passenger Frontal Stage 2 Deployment Control
B0005
Driver Knee Airbag Deployment Circuit
B0006
Passenger Knee Airbag Deployment Circuit
B0007
Rear Left Side Airbag Deployment Circuit
B0008
Rear Right Side Airbag Deployment Circuit
B0010
Driver Side Airbag Deployment
B0011
Driver Side Airbag Deployment Circuit Open