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

P26CE

Engine Coolant Pump Overspeed/Air In System

The coolant pump speed feedback is higher than the commanded value with no resistance from coolant. Indicates air in the cooling loop or low coolant level so the pump spins free.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number6 / CE

Possible causes

  • Low coolant level due to leak or improper fill high
  • Air pocket trapped in the cooling loop medium

Inspection / repair

  • Difficulty: easy
  • DIY: possible
  • Estimated cost: 30–300 €
  • Estimated time: 0.3–2 h
  • Component: engine coolant pump
  • Component: cooling system
  • Component: coolant reservoir
  • 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