P284EShift Fork B Unrequested Movement
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P284E reports that fork B drifted while no shift was asked for. GM's 2023 Corvette dual-clutch table describes the test on rod 2 in detail: with no actuating force applied, the measured position must stay inside wide limits around the learned point of the gear verified as engaged by clutch-shaft and output speed readings; leaving them for 500 ms is a fault. The code also sets if the drift correction, which acts on narrower limits, triggers ten times or stays active for over 5 s. The DTC is Type A and launches a resynchronization routine on the odd shaft. Ford's TR9070 documentation from 2024 assigns P284E to drift of shift rod 2, and Mercedes-Benz lists P284E00 for its 8G-DCT as fork B moving on its own.
- What you may notice
- Gear on the odd shaft pops out or is re-engaged with a jolt
- Warning lamp, possible limp-home mode
- Likely causes
- LikelySynchronizer pressure valve for fork B leaking and pushing the rod
- PossibleWeak detent or worn gear dog teeth on fork B gears
- PossibleOutdated learned engaged positions
- 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: €150 – €3,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.