C0310 code meaning
Transfer Case Motor A/B Circuit Open
What C0310 means
C0310 is not listed in any publicly available J2012 table; no maker uses it for a rear left ride height sensor. GM assigns the number to the transfer case shift motor: it is in PIP5094, AA1Car gives the GM wording Motor A/B Circuit Open, and Dorman describes it for GM trucks and SUVs of 1998 to 2005. The transfer case module drives the motor through two lines, one switched to supply and the other to ground depending on direction. When it commands a low level on a line and reads a high voltage back instead, it concludes that line A, line B or the motor winding is open and stores C0310. Shifting is then blocked and Service 4WD lights up. A broken motor pigtail or connector is the usual cause.
C0310 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 C0310
- Service 4WD lamp on, 4WD switch lights flash
- Transfer case stays in its last range
Common causes of C0310
- Most likelyBroken motor control wire or pigtail exposed under the vehicle
- PossibleCorroded or unseated connector at the shift motor
- PossibleOpen winding or worn brushes in the shift motor
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 C0310 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 10 | The exact fault in that area. |
What to do next
- Note C0310 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 C0310
What does C0310 mean?
C0310 means "Transfer Case Motor A/B Circuit Open". C0310 is not listed in any publicly available J2012 table; no maker uses it for a rear left ride height sensor. It is a generic code, so it means the same on every make.
Is it safe to drive with C0310?
Drive gently and only to a workshop. With C0310 the car can go into limp mode (reduced power) to protect itself.
Will C0310 fail an emissions test?
C0310 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 C0310 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 C0310 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.