P283CShift Fork C Position Circuit Range/Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P283C is the plausibility code for fork C, which GM's 2023 Corvette table assigns to rod 3 on the even-gear shaft. Besides the force and speed comparison during shifts (over 600 N, more than 1100 µm off the learned point, Type A), a static monitor runs here: with no shift force on the rod, the reading must stay inside tolerance bands around the learned neutral or engaged point. A drift is only confirmed once clutch speed can be checked against engine speed and output speed against the driven wheels. A confirmed fault triggers recovery of the even shaft synchronizer. Ford's TR9070 uses P283C for rod sensor 3 consistency and logs drift separately as P277E, while Mercedes-Benz describes it as a malfunction of the fork C sensor on the 8G-DCT.
- What you may notice
- Even gears drop out or refuse to engage
- Grinding or a knock during shifts on the even shaft
- Warning lamp, gearbox limits gear choice
- Likely causes
- LikelyRod 3 creeping out of position because of worn detent or fork
- PossiblePosition values not relearned after gearbox or sensor work
- PossibleSynchronizer actuation on the even shaft not reaching target position
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €150 – €3,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.