P2852Shift Fork Position Sensor C/D Correlation
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P2852 pairs the position sensors of forks C and D and sets when their readings do not fit together. In GM's numbering these are rods 3 and 4, both on the even shaft and fed from the second sensor reference; a reference fault there would shift both signals together. No published OBD summary actually uses P2852: GM keeps rods 3 and 4 apart with P283C and P2841, and Ford's TR9070 lists consistency faults for shift rod sensors 3 and 4 in the same two codes. CARB 13 CCR 1968.2 is therefore the only basis. Diagnosis starts with the two signals in live data while each fork is moved by a scan-tool test; if both deviate in the same direction, wiring or supply is more likely than the sensors themselves.
- What you may notice
- Gears of forks C and D unavailable
- Transmission fault message, reduced power
- Likely causes
- LikelyReference voltage feeding the C and D sensors out of tolerance
- PossibleSensor C or D reporting a shifted value
- RareInput circuit fault in the transmission module
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.