Code
P2641
Generic
P — Powertrain
Torque Management Feedback Signal B
AI status
Completed
Completed
100%
Causes
- Open, shorted, or damaged wiring in the torque management feedback B circuit
- Corroded, loose, or contaminated connector at the sensor/actuator or PCM
- Failed torque management sensor, feedback sensor, or actuator
- Faulty PCM or torque management control module hardware or software
- Insufficient battery/charging system voltage or poor ground connection
- Mechanical binding or failure of the torque control actuator/assembly
Symptoms
- Malfunction Indicator Lamp (MIL) / Check Engine Light illuminated
- Reduced engine performance or engine derate/limp mode in some vehicles
- Irregular or reduced torque control and drivability issues
- Possible rough idle, hesitation under load, or abnormal shifting behavior
- Diagnostic trouble code stored and may be repeatable on demand
What to check
- Read and record freeze frame and related codes with a scan tool; note conditions when the code set
- Visually inspect wiring harnesses and connectors for damage, corrosion, or moisture at the sensor/actuator and PCM
- Verify battery voltage and good ground connections at the engine and PCM
- Backprobe the feedback B signal, power, and ground while monitoring with a DVOM or oscilloscope
- Check connector pin continuity to the PCM and for resistance to specification
- Wiggle harness while monitoring signal to detect intermittent faults
Signal parameters
- Typical feedback type: low-voltage analog signal or PWM referenced to vehicle 5 V system (varies by manufacturer)
- Common voltage range: approximately 0–5.0 V (exact idle/loaded values are vehicle-specific)
- Some systems use frequency or duty-cycle feedback — may appear as 0–2000 Hz or variable duty on a scope
- Good reference and ground required; signal should be stable and proportional to torque demand
- Compare live data to known-good values or manufacturer specifications for the specific vehicle
Diagnostic algorithm
- Use a scan tool to read DTCs, freeze frame data, and live data for torque feedback B. Record related codes.
- Clear the code and attempt to reproduce to confirm fault is active and to capture updated freeze frame.
- Perform a thorough visual inspection of the sensor/actuator B, connectors, and wiring to the PCM. Repair obvious damage.
- With ignition ON (engine off) backprobe power and ground terminals at the sensor/actuator to verify proper supply voltage and ground.
- Backprobe the feedback B signal and monitor with a multimeter or oscilloscope while commanding torque changes (or during a road test) to observe expected variation.
- Check continuity and resistance between the sensor/actuator connector and the PCM pin to locate opens or shorts; repair any harness faults.
- If wiring and connectors are good, swap or bench-test the sensor/actuator with a known-good unit if available.
- If the component tests OK, verify PCM supply voltages, grounds, and check for PCM-related DTCs; consider reprogramming or replacing PCM if indicated by manufacturer procedures.
- After repairs, clear codes and perform a complete functional test and road test to ensure the fault does not return.
Likely causes
- Damaged or chafed wire between feedback sensor/actuator B and PCM
- Corroded connector pins or water intrusion at the sensor/actuator or PCM connector
- Defective torque feedback sensor or actuator (internal failure)
- Intermittent open/short to voltage or ground caused by harness damage
- PCM software anomaly or internal fault (less common)
Fault status
Status
Torque Management Feedback Signal B circuit malfunction — abnormal, missing, or out-of-range signal detected by PCM.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
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