P2864Shift Fork E Position Circuit Range/Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- P2864 sets when the fork E position signal is electrically fine but contradicts what the shaft speeds show. GM's 2023 Corvette dual-clutch table uses it as the Type A consistency check of rod 5, which belongs to the even-gear clutch shaft. During an engagement with more than 600 N of rod force, the code matures if speeds prove the gear is in but the sensor stays over 1100 µm from the learned engaged point; similar tests run during disengagement, at rest (500 ms with clutch and output speeds cross-checked), and in an intrusive routine that expects at least 100 µm of travel. GM also uses P2864 to start a synchronizer recovery routine. Mercedes-Benz lists P286400 as a fork E sensor malfunction on the 8G-DCT. A relearn is the usual first step.
- What you may notice
- Gears on fork E locked out, warning lamp on
- Harsh or aborted shifts on the even shaft
- Reduced performance mode
- Likely causes
- LikelyLearned positions of rod 5 missing or outdated after repair or software update
- PossibleSensor magnet on the fork E rod shifted or loose
- PossibleSynchronizer actuation valve for rod 5 sticking, so the rod barely moves
- RareImplausible even-shaft or output speed signal misleading the check
- 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: €80 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.