U0115critical severityNetwork
Lost Communication with ECM/PCM B
on 2007 Audi S6 5.2L V10 · AWD
What this code means
Cannot communicate with the secondary Engine Control Module on vehicles with dual ECMs.
Symptoms
- Partial engine management failure
- Some cylinders not controlled
- Reduced power
- Check Engine Light
Common causes
- ECM B power failure
- CAN bus wiring
- ECM B failure
- Fuse blown
- Connector issue
Diagnostic steps
- Check ECM B fuse
- Test power and ground
- Check CAN wiring
- Try direct communication with ECM B
- Compare ECM A and B communication status
Repair notes
Dual ECM vehicles are less common. Check power supply to secondary ECM.
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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