P2551 — Torque Management Request Input Signal B High

P2551: Torque Management Request Input Signal B High — what it means, the affected system and what to check before replacing parts.

Meaning, symptoms, causes and checks

Torque-management request input B is reported electrically high. A high input signal does not independently prove excessive physical engine torque.

Affected system: Powertrain

Symptoms

  • Warning light may illuminate
  • Related system function may be impaired
  • Vehicle-specific symptoms vary

Possible causes

  • Implausible sensor or switch signal, poor ground, connector corrosion, or wiring damage
  • Related wiring, connector, power or ground fault
  • Vehicle-specific mechanical or control issue

What to check

  • Record stored and pending codes and freeze-frame data
  • Compare the named sensor or switch signal with actual operating conditions; inspect the connector, reference supply, ground and harness.
  • Confirm measured values against the vehicle service information
  • Retest under the conditions that set the code
  • Compare the named sensor or switch signal with actual operating conditions; inspect the connector, reference supply, ground and harness.
  • Repair the verified cause and confirm the code does not return

Also written as: P2551-00, P255100 (some scan tools add the fault-type byte, e.g. -00).