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

P2543

Power Demand Signal Circuit

The ECU detects an electrical fault on the power demand input signal used to coordinate accessory loads (e.g. AC compressor, alternator load). The signal is missing or implausible.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number5 / 43

Possible causes

  • Open signal wire high
  • Fault in requesting module medium

Inspection / repair

  • Difficulty: medium
  • DIY: possible
  • Estimated cost: 80–400 €
  • Estimated time: 0.3–1.5 h
  • Component: power demand signal module
  • Component: hvac module
  • 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