U0100critical severityNetwork
Lost Communication with ECM/PCM
on 2008 Audi R8 4.2L V8 · AWD
What this code means
The diagnostic system cannot communicate with the Engine Control Module.
Symptoms
- Multiple warning lights
- Engine may not start
- Many systems inoperative
- Cannot read engine codes
Common causes
- PCM power or ground failure
- CAN bus wiring issue
- PCM failure
- Fuse blown
- Wiring harness damage
Diagnostic steps
- Check PCM fuses
- Test PCM power and ground circuits
- Check CAN bus wiring to PCM
- Try communicating with other modules
- Inspect wiring harness
Repair notes
Check fuses and power supply to PCM first. CAN bus issue is second most common.
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Other Network codes on this vehicle
00003
Control Module - Defective
01304
Radio - No Communication
01312
Powertrain Data Bus - Defective
01314
Engine Control Module (ECM) - no communications
01315
Transmission Control Module (TCM) - No Communication
01316
ABS Control Module - No Communication
01317
Instrument Cluster Control Module (J285) - No Communication
01318
Immobilizer Control Module - No Communication
01321
Airbag Control Module - No Communication
U0001
High Speed CAN Communication Bus