P284BShift Fork C Stuck
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P284B reports a third fork that refuses to travel. Two situations matter: stuck in neutral, which merely costs the gears of fork C, and stuck in an engaged gear, which is more serious because that shaft then turns with a fixed ratio and a second gear on the same shaft must never be selected. No published OBD strategy assigns P284B, so the code rests on what CARB 13 CCR 1968.2 demands for transmission parts. A hydraulic counterpart can be seen in GM's Corvette table, where stuck-on and stuck-off failures of the selector pilot valve, which steers oil to the rods, set P282A and P2829. Before replacing parts, check fluid level and condition and any valve or actuator codes, since a fork rarely jams without a reason upstream.
- What you may notice
- Car stays in one gear on one shaft or skips the fork C gears
- Transmission warning lamp
- Likely causes
- LikelySelector or pilot valve not routing pressure to the fork C rod
- PossibleLow or degraded transmission fluid
- PossibleFork C or its rod mechanically jammed
- 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: €300 – €4,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.