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

P26BD

Engine Coolant Bypass Valve D Control Circuit / Open

The controller cannot drive the fourth coolant bypass valve.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number6 / BD

Possible causes

  • Open coil in bypass valve solenoid high
  • Broken control wire medium

Inspection / repair

  • Difficulty: medium
  • DIY: shop recommended
  • Estimated cost: 150–900 €
  • Estimated time: 1–3.5 h
  • Component: coolant bypass valve d
  • Component: solenoid
  • Component: wiring harness
  • 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