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

P0EA9

Auxiliary Cooling System Performance

The auxiliary cooling system performance is below calibration. Coolant flow or temperature drop insufficient under load.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / numberE / A9

Possible causes

  • Aux pump output degraded high
  • Radiator partially blocked medium

Inspection / repair

  • Difficulty: medium
  • DIY: shop recommended
  • Estimated cost: 200–1500 €
  • Estimated time: 1–6 h
  • Component: aux cooling pump
  • Component: aux cooling radiator
  • Component: aux cooling fan
  • MIL / check engine light
  • limp mode possible

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