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

P0531

A/C Refrigerant Pressure Sensor Range/Performance

The A/C refrigerant pressure sensor signal is implausible against operating conditions. Reading does not change as expected when the compressor cycles or ambient conditions change.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number5 / 31

Possible causes

  • Pressure sensor drift high
  • Refrigerant charge incorrect medium
  • Wiring fault low

Inspection / repair

  • Difficulty: medium
  • DIY: shop recommended
  • Estimated cost: 80–400 €
  • Estimated time: 0.3–1.5 h
  • Component: ac pressure sensor
  • Component: ac compressor

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