P2639
Torque Management Feedback Signal A Low
The torque feedback signal A reads below its valid range. Either the source reports a value below physical possibility or the bus signal is stuck low.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Source module sends invalid low valueCommon
- Signal stuck low on the busPossible
Parts involved
- TCM
- Communication Bus
P2639 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.