OBD-II reference

All 9.533 generic OBD-II codes, explained in detail.

Causes, inspection steps and sources — a comprehensive DIY archive. Created and maintained with love for the detail. Good luck and have fun!

Powertrain generic / SAE

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.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number6 / 39

Possible causes

  • Source module sends invalid low value high
  • Signal stuck low on the bus medium

Inspection / repair

  • Difficulty: medium
  • DIY: shop recommended
  • Estimated cost: 150–1500 €
  • Estimated time: 1–4 h
  • Component: tcm
  • Component: communication bus
  • MIL / check engine light

Sources

References

How to read OBD-II codes

The first letter names the vehicle system, the second digit distinguishes generic from manufacturer-specific, the remaining digits group fault area and number.

PPowertrain: engine, transmission, emissions
BBody: chassis trim, comfort, interior
CChassis: suspension, brakes, steering
UNetwork: CAN, control modules, communication