P2551Torque Management Request Input Signal B High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- P2551 is the high-side fault of torque request B: the signal sits above the top of its valid window. Typical electrical causes would be a line touching a battery feed, an interrupted reference ground or a sender that drives its output to full scale. Because an unexpectedly high request could translate into unwanted torque, the engine module discards it and works without channel B. No maker documents P2551 publicly. GM's ECM table 17OBDG04 shows that a vehicle can fill channel B with the brake and traction module's request and validates it with protection value and message counter under P2548, with no separate high code. CARB requires monitoring of such electronic inputs whenever a failure could raise emissions or blind another monitor. P2550 is the low-side fault, P2547 the high fault on input A.
- What you may notice
- Check engine light depending on make
- Traction control warning, engine ignores intervention requests
- Likely causes
- PossibleRequest line shorted to battery voltage
- PossibleOpen ground or reference at the sender
- RareRequesting module drives its output to full scale
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €700
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.