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

P2122

Throttle/Pedal Position Sensor "D" Circuit Low

Sensor "D" of the redundant accelerator-pedal pair reports a voltage below the valid window. The ECU rejects the signal and falls back on the second sensor or limp-home.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number1 / 22

Possible causes

  • Pedal sensor track worn high
  • Signal wire shorted to ground medium
  • Connector pins corroded - high contact resistance low

Symptoms

  • Check engine light on
  • Reduced throttle response, possible limp mode
  • Hesitation or surging
  • Idle too high or too low

Inspection / repair

  • Difficulty: easy
  • DIY: possible
  • Estimated cost: 80–350 €
  • Estimated time: 0.3–1.5 h
  • Component: accelerator pedal sensor
  • Component: accelerator pedal wiring
  • MIL / check engine light
  • emissions-relevant
  • drive cycle required
  • 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