U0102
NetworkModule Communicationhigh severityLost Communication with Transfer Case Control Module
What U0102 Means
Cannot communicate with the transfer case control module that manages AWD/4WD operation.
Symptoms
- 4WD/AWD warning light on
- Transfer case stuck in mode
- Cannot switch between 2WD and 4WD
- Service 4WD message
Common Causes
- Transfer case module power failure
- CAN bus wiring to module
- Transfer case module failure
- Fuse blown
- Connector corrosion
Diagnostic Steps
- Check transfer case module fuse
- Test module power and ground
- Inspect CAN bus wiring to module
- Try direct communication with module
- Check connector for corrosion
Where to start: Check fuses and power supply first. Common on trucks after water fording.
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