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

P23C7

Fuel Heater Control Module Power Control Circuit Open

The control line that energises the fuel heater control module - used on diesel systems for cold-weather fuel preheating - is open.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number3 / C7

Possible causes

  • Open in control wiring high
  • Pin pushed back out of connector body low
  • Cracked solder joint inside the module or sensor low

Inspection / repair

  • Difficulty: medium
  • DIY: possible
  • Estimated cost: 120–450 €
  • Estimated time: 0.6–2 h
  • Component: fuel heater control module
  • 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