P2639 moderate

Torque Management Feedback Signal A Low

The P2639 code means the vehicle's onboard diagnostic system has detected: Torque Management Feedback Signal A Low. This is a moderate severity code.

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Keep driving?
Short distances only
DIY difficulty
hard
Estimated cost
$100 - $800 (parts and labor)
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Common Symptoms

  • Transmission flares during shifts
  • Delayed engagement from stop
  • Reduced power feeling
  • Check engine and traction lights on

Probable Causes (Ranked by Likelihood)

  • ECM torque output signal low Very High
  • Ground fault in torque signal circuit High
  • ECM underreporting torque due to sensor error Moderate
  • TCM receiving attenuated signal Low

Step-by-Step Diagnostic Procedure

  1. Monitor reported torque vs expected for current load

  2. Check torque signal wiring for ground faults

  3. Verify MAP/MAF and throttle sensors are accurate

  4. Test CAN bus signal integrity

Frequently Asked Questions

Why does my transmission flare with P2639?

The TCM thinks engine torque is lower than actual, so it does not apply enough clutch pressure during shifts, causing RPM flare between gears.

What is a transmission flare?

A flare occurs when engine RPM rises momentarily between shifts instead of transitioning smoothly. It feels like the transmission briefly slips.

Can P2639 damage my transmission?

Prolonged shifting with incorrect torque data can cause increased clutch wear and overheating. Repair to prevent long-term transmission damage.

Sources

This page is built from documented references. Verify against your own service info before repair work.

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