U0138
NetworkModule Communicationmoderate severityLost Communication with All Terrain Control Module
What U0138 Means
Cannot communicate with the off-road or terrain management control module.
Symptoms
- Off-road mode not available
- Terrain select not working
- 4WD features limited
- Terrain response warning
Common Causes
- Terrain module failure
- CAN bus wiring
- Module power loss
- Fuse blown
Diagnostic Steps
- Check terrain module fuse
- Test power and ground
- Check CAN wiring
- Test terrain mode switch
- Scan for terrain module DTCs
Where to start: Check fuses and mode selector switch. Module may be integrated with transfer case controller.
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