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

P2604

Coolant Pump Control Circuit High

The electric coolant pump drive line reads above the upper threshold — usually a short to positive or a stuck-on driver stage.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number6 / 04

Possible causes

  • Drive line shorted to positive high
  • Driver stage shorted on medium
  • Connector pins corroded - high contact resistance low

Inspection / repair

  • Difficulty: medium
  • DIY: possible
  • Estimated cost: 120–700 €
  • Estimated time: 0.5–2.5 h
  • Component: electric coolant pump
  • Component: coolant pump wiring
  • MIL / check engine light
  • emissions-relevant
  • drive cycle required

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