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

P23C6

Engine Coolant Bypass Valve C Control Circuit Driver Current or Temperature Too High

The driver stage of the coolant bypass valve C reports excessive current draw or thermal protection trip - typically a sticking valve drawing too much motor current.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number3 / C6

Possible causes

  • Motor overloaded by jammed valve high

Symptoms

  • Check engine light on
  • Cooling fan runs constantly or not at all
  • Cabin heater weak or excessively hot
  • Possible long warm-up time or hard cold start

Inspection / repair

  • Difficulty: medium
  • DIY: possible
  • Estimated cost: 200–800 €
  • Estimated time: 1–3.5 h
  • Component: coolant bypass valve c
  • 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