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

P26C2

Engine Coolant Bypass Valve D Stuck Closed

The fourth coolant bypass valve is stuck closed.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number6 / C2

Possible causes

  • Valve seized closed by debris high
  • Actuator linkage jammed in closed position medium
  • Carbon or debris buildup preventing free movement low

Inspection / repair

  • Difficulty: medium
  • DIY: possible
  • Estimated cost: 80–600 €
  • Estimated time: 0.5–2.5 h
  • Component: coolant bypass valve d
  • Component: thermostat housing
  • 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