U0138moderate severityNetwork
Lost Communication with All Terrain Control Module
on 2008 Subaru Legacy 3.0L H6 · AWD
What this code 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
Repair notes
Check fuses and mode selector switch. Module may be integrated with transfer case controller.
Other Network codes on this vehicle
U0001
High Speed CAN Communication Bus
U0002
High Speed CAN Communication Bus Performance
U0003
High Speed CAN Communication Bus (+) Open
U0004
High Speed CAN Communication Bus (+) Low
U0005
High Speed CAN Communication Bus (+) High
U0006
High Speed CAN Communication Bus (-) Open
U0007
High Speed CAN Communication Bus (-) Low
U0008
High Speed CAN Communication Bus (-) High
U0009
High Speed CAN Communication Bus Shorted Together
U0010
Medium Speed CAN Communication Bus