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

P0380

Glow Plug/Heater Circuit "A" Malfunction

The glow plug control module reports an electrical fault on circuit A — typically a single glow plug open-circuit, the relay failing, or wiring to the harness damaged. Diesel-specific; affects cold-start behaviour.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number3 / 80

Possible causes

  • One or more glow plugs open-circuit high
  • Glow plug relay failed medium
  • Wiring/harness damage low

Symptoms

  • Glow plug warning light on (often orange coil symbol)
  • Hard cold start or no start in cold weather
  • White smoke from exhaust during warm-up

Inspection / repair

  • Difficulty: medium
  • DIY: possible
  • Estimated cost: 80–500 €
  • Estimated time: 0.5–3 h
  • Component: glow plug
  • Component: glow plug relay
  • Component: glow plug 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