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

P26D1

Engine Coolant Pump Control Module System Voltage High

The smart coolant pump module reports the system voltage above operating range. Pump output is reduced or disabled to protect the module.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number6 / D1

Possible causes

  • Alternator regulator failed to limit output high
  • Load dump transient after disconnecting a heavy load low

Inspection / repair

  • Difficulty: medium
  • DIY: shop recommended
  • Estimated cost: 150–1000 €
  • Estimated time: 1–3.5 h
  • Component: smart coolant pump module
  • Component: charging system
  • 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