OBD-II code · Powertrain (generic, extended)

P2551 Torque Management Request Input Signal B High

Torque management input B reads stuck high — short to reference voltage or message at maximum. ECM rejects the request to avoid unintended high-torque commands.

Is it safe to drive with P2551?

Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.

Common causes

  • Most likelySignal wire shorted to reference voltage

Repair at a glance

Difficulty
Hard
DIY friendly
Best left to a mechanic
Typical labour
0.5–3 h
Emissions test
Usually unaffected
Parts involved
Torque Management Input B

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.