C0308 code meaning
Transfer Case Motor A/B Circuit Low
What C0308 means
None of the publicly available J2012 lists contains C0308, and no source links it to a ride height sensor. GM uses it for the transfer case shift motor: PIP5094 lists the number, AA1Car's GM chart labels it Motor A/B Circuit Low, and Dorman's guide for its replacement motor covers 1998–2005 S10 Blazer, Sonoma, Tahoe, Suburban, Yukon, Silverado, Sierra, Escalade, Avalanche and related trucks. The transfer case module sets it when it finds motor control line A or B shorted to ground, or when the feedback voltage on those lines is far too low. Once stored, the module stops every 4WD shift and lights Service 4WD. The sibling codes C0309 and C0310 cover a high voltage and an open circuit on the same lines.
C0308 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C0308
- Service 4WD lamp on
- No shifting into or out of four-wheel drive
Common causes of C0308
- Most likelyMotor control wire A or B chafed against the frame and grounded
- PossibleShift motor internally shorted
- Less likelyTransfer case control module output stage faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Transfer case control moduleShift motorTransfer case wiring
What each part of C0308 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 08 | The exact fault in that area. |
What to do next
- Note C0308 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 C0308
What does C0308 mean?
C0308 means "Transfer Case Motor A/B Circuit Low". None of the publicly available J2012 lists contains C0308, and no source links it to a ride height sensor. It is a generic code, so it means the same on every make.
Is it safe to drive with C0308?
Drive gently and only to a workshop. With C0308 the car can go into limp mode (reduced power) to protect itself.
Will C0308 fail an emissions test?
C0308 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 C0308 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will C0308 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.