B0101high severityBody
Immobilizer Transponder Signal Not Detected
on 1998 BMW 318i 1.9L I4 M44 · RWD
What this code means
The immobilizer system cannot detect the transponder signal from the key. The engine will not start.
Symptoms
- Engine cranks but will not start
- Security light flashing
- Key symbol on dashboard
- No-start condition
Common causes
- Dead key battery (smart key)
- Faulty transponder chip in key
- Damaged antenna ring around ignition
- Interference from other transponder keys
- Key handle cracked exposing transponder to damage
Diagnostic steps
- Try different registered key
- Hold key closer to ignition/start button
- Check for key battery (if applicable)
- Test antenna ring with known-good key
- Scan immobilizer codes
Repair notes
Replace key battery or have new key programmed. Replace antenna ring if faulty.
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
B0010
Driver Side Airbag Deployment
B0011
Driver Side Airbag Deployment Circuit Open
B0012
Driver Side Airbag Deployment Circuit Short to Ground
B0013
Driver Side Airbag Deployment Circuit Short to Battery