P2639 indicates that the engine control module is receiving a low torque management feedback signal, which it uses to regulate engine torque output. The code is triggered when the signal falls below the expected voltage range during operation.
A failing throttle actuator can produce an abnormally low feedback voltage, causing the PCM to set P2639. This is the most common hardware failure.
Some engines use a dedicated torque sensor or rely on data from other sensors to estimate torque; a fault in this sensor can lower the reported feedback.
Corroded, damaged, or loose terminals can interrupt the signal between the actuator/sensor and the PCM, resulting in a low reading.
The PCM's internal driver that supplies the torque feedback signal can fail, but this is less common and usually accompanied by additional PCM‑related codes.
A severe fault in a linked sensor can cause the PCM to misinterpret torque demand and trigger the low‑feedback condition.
No. In the majority of cases the cause is a faulty actuator, sensor, or wiring issue, not a defective PCM.
Low oil pressure is not a typical trigger for P2639; the code relates specifically to the torque feedback signal, not oil conditions.
The engine may appear normal initially, but if the underlying fault remains, the code will return and the powertrain may continue to limit power.