C0387 code meaning
Transfer Case Unable to Complete Shift
What C0387 means
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.
C0387 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C0387
- Service 4WD message, often intermittent
- Requested range or mode is not reached
- Transfer case stays in a default 4HI or 4LO
Common causes of C0387
- Most 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
- Less likelyMechanical binding inside the transfer case shift mechanism
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Encoder motorTransfer case control moduleTransfer case position sensor
What each part of C0387 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 87 | The exact fault in that area. |
What to do next
- Note C0387 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about C0387
What does C0387 mean?
C0387 means "Transfer Case Unable to Complete Shift". C0387 is absent from the publicly available J2012 lists. It is a generic code, so it means the same on every make.
Is it safe to drive with C0387?
Drive gently and only to a workshop. With C0387 the car can go into limp mode (reduced power) to protect itself.
Will C0387 fail an emissions test?
C0387 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is C0387 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will C0387 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.