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

P2135

Throttle/Pedal Position Sensor "A"/"B" Voltage Correlation

The two redundant throttle position sensors on the throttle body disagree by more than allowed. Distinct from P2138 which monitors the pedal pair — P2135 monitors the throttle-body pair on drive-by-wire systems.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number1 / 35

Possible causes

  • Throttle position sensor track worn high
  • Corrosion on throttle body connector medium

Symptoms

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

Inspection / repair

  • Difficulty: medium
  • DIY: possible
  • Estimated cost: 120–600 €
  • Estimated time: 0.5–2 h
  • Component: throttle position sensor
  • Component: throttle body
  • 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