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

P2538

Ignition Switch Accessory Position Circuit High

The ACC input reads stuck high — short to battery voltage. The ECM cannot detect when the operator releases the switch from ACC, accessory power timeouts do not work.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number5 / 38

Possible causes

  • ACC wire shorted to battery voltage high
  • Connector pins corroded - high contact resistance low
  • Supply wire pinched against B+ source low

Inspection / repair

  • Difficulty: medium
  • DIY: shop recommended
  • Estimated cost: 80–500 €
  • Estimated time: 0.5–2 h
  • Component: ignition switch
  • Component: wiring harness
  • 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