C0310Transfer Case Motor A/B Circuit Open
- Generic OBD-II code · Chassis
- Can trigger limp mode
- How the car detects it
- 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.
- What you may notice
- Service 4WD lamp on, 4WD switch lights flash
- Transfer case stays in its last range
- Likely causes
- 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
- Repair
- Medium · Often possible to do yourself.Typical cost: €20 – €700
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.