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DTC codes / P25xx · Vehicle speed, idle control and auxiliary inputs / P2548

P2548Torque Management Request Input Signal 'B'

P2548 indicates that the powertrain control module (PCM) has detected an implausible or out-of-range signal on the torque management request input circuit designated as 'B'. This input is used by the PCM to coordinate torque reduction requests from systems such as the transmission controller or stability control, and the code sets when the signal voltage or message does not match expected values under the current operating conditions.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaVehicle speed, idle control and auxiliary inputs

Symptoms you may notice

  • Illumination of the check engine light, often with no other noticeable symptoms
  • Harsh or delayed transmission shifts as torque management intervention is disabled
  • Reduced engine power or a limp-home mode in some vehicles
  • Inconsistent throttle response or hesitation during acceleration
  • Traction control or stability control warning light may also be illuminated
  • Poor fuel economy or increased emissions in rare cases

Common causes, most likely first

  1. Faulty torque management request sensor or switch (signal 'B')
  2. Damaged, corroded, or shorted wiring in the signal 'B' circuit
  3. Loose or corroded electrical connector at the sensor or PCM
  4. Failed or malfunctioning PCM (rare but possible)
  5. Software calibration issue in the PCM requiring reflash
  6. Aftermarket electronic modifications interfering with the signal circuit
  7. Water intrusion or physical damage to the sensor or harness

How to diagnose and fix it

  1. Use an OBD-II scanner to verify P2548 is the only stored code and check for related pending codes
  2. Inspect the torque management request sensor and its connector for corrosion, damage, or loose pins
  3. Perform a visual inspection of the wiring harness for chafing, shorts, or opens, especially near hot or moving components
  4. Measure the signal voltage on circuit 'B' with a multimeter and compare to the manufacturer's specification
  5. Check the sensor's resistance or output signal with a scan tool while manipulating the throttle or driving
  6. If the sensor and wiring test good, check for technical service bulletins (TSBs) or software updates for the PCM
  7. Replace the faulty sensor or repair the wiring as needed, then clear codes and verify the repair with a test drive

What the torque management signal 'B' really does

  • The torque management request input 'B' is often a redundant or secondary signal used for plausibility checks, so a fault may not cause any drivability symptoms until the system disables torque intervention.
  • A common misdiagnosis is replacing the PCM when the actual problem is a chafed wire in the harness near the transmission bell housing or exhaust manifold.
  • On some vehicles, the signal 'B' circuit is shared with the traction control system, so a fault in the wheel speed sensor circuit can set P2548 as a secondary code.
  • Aftermarket tuners or piggyback modules that intercept torque signals frequently cause this code by altering the expected voltage range.
  • Always check for a loose or missing ground connection at the transmission or chassis, as a bad ground can corrupt the signal 'B' reference voltage.

Can I keep driving with P2548?

The vehicle is generally safe to drive with P2548, but you may experience harsh shifts or reduced performance; avoid aggressive acceleration or towing until the fault is repaired, and have the system diagnosed promptly to prevent transmission wear.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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