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

P2548

Torque Management Request Input Signal B

General electrical fault on the second torque-management request input B. Used when more than one module needs to request torque adjustments — typically TCM on input A and ABS/ESC on input B, or chassis vs powertrain. With B invalid, only the A-side request is honoured.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number5 / 48

Possible causes

  • Open or shorted wire / invalid CAN message high

Inspection / repair

  • Difficulty: hard
  • DIY: shop recommended
  • Estimated cost: 120–800 €
  • Estimated time: 0.5–3 h
  • Component: torque management input b
  • 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