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

P262D

Sensor Reference Voltage G Circuit Low

The 5 V reference G voltage is below the expected level. Usually a short to ground or excessive load from a downstream sensor pulling the rail down.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number6 / 2D

Possible causes

  • Reference wire shorted to ground high
  • Sensor on the rail shorted internally to ground medium
  • Connector pins corroded - high contact resistance low

Inspection / repair

  • Difficulty: medium
  • DIY: shop recommended
  • Estimated cost: 120–1200 €
  • Estimated time: 0.8–4 h
  • Component: control module
  • Component: reference voltage rail
  • Component: sensors on rail g
  • 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