C0387Transfer Case Unable to Complete Shift
- Generic OBD-II code · Chassis
- Can trigger limp mode
- How the car detects it
- C0387 is absent from the publicly available J2012 lists. GM uses it in its transfer case control module as Unable to Complete Shift; there is no evidence of a position sensor code. PIP5003C for 2010–13 Silverado, Sierra, Tahoe, Yukon, Avalanche, Escalade and hybrids explains that once a range change or a slip correction has been commanded, the module watches the shift shaft and sets the code when the motor has not begun to move it within 50 ms; heat, cold and supply voltage influence this. If it is history only and cannot be reproduced, a slow encoder motor is the likely culprit, not the module. PIP5080 has technicians check terminal fit in plugs X109 and X3. Per PIP5089A, if the fault is still present at the next start the failed relearn sets C0569 instead. Dorman adds that the module may default to 4HI or 4LO.
- What you may notice
- Service 4WD message, often intermittent
- Requested range or mode is not reached
- Transfer case stays in a default 4HI or 4LO
- Likely causes
- LikelyEncoder motor too slow to start moving the shift shaft
- PossiblePoor terminal fit at the module connectors (GM X109, X3)
- PossibleLow supply voltage or extreme temperatures during the shift
- RareMechanical binding inside the transfer case shift mechanism
- Repair
- Medium · Usually a job for a workshop.Typical cost: €30 – €800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.