P2640: Torque Management Feedback Signal A Circuit High
What to do
The engine responds normally while the gearchanges have become hard or jolting. That combination is worth reporting precisely, because a gearbox that bangs into gear on a car whose engine is perfectly smooth is very often a signalling fault rather than a transmission fault. The transmission is applying clutch pressure for a torque figure much larger than the engine is actually producing.
No gearbox work should be authorised on the strength of this. The wiring between the modules is the place to look, and a scan tool comparing what each module believes the engine torque to be shows the disagreement immediately.
What this code means
The torque feedback circuit reads above its valid range — an open circuit, a disconnected connector, or a short to supply.
An open circuit gives the honest failure: no answer, and receiving modules that know there is no answer and fall back accordingly, as at P2637.
A short to supply is the more troublesome case, because it reports maximum torque continuously. A transmission told the engine is producing far more torque than it is will apply more clutch pressure than the shift needs, which produces the hard, jolting changes that get read as a failing gearbox. Nothing is being damaged — the pressure is high rather than low — but the complaint is loud and it points at the wrong component.
Likely causes
Start here
- Open circuit in sensor wiring · moderate
- Wiring shorted to voltage · moderate
- Corroded or loose connector · easy
Less common
- Disconnected sensor connector · easy
- Faulty transmission control module · specialist
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
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