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

P0629

Fuel Pump A Control Circuit High

The control circuit for fuel pump A reports voltage below the lower diagnostic threshold. Indicates short to ground or open winding.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number6 / 29

Possible causes

  • Pump circuit shorted to power high
  • Ground open medium
  • Connector pins corroded - high contact resistance low

Symptoms

  • Check engine light on
  • Hard start, no start, or stalling under load
  • Power loss especially at high load or rpm
  • Possible long cranking time

Inspection / repair

  • Difficulty: medium
  • DIY: shop recommended
  • Estimated cost: 120–800 €
  • Estimated time: 0.5–3 h
  • Component: fuel pump
  • Component: fuel pump relay
  • Component: pump wiring
  • MIL / check engine light
  • emissions-relevant
  • limp mode possible

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