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

P24F2

EGR Temperature/Charge Air Cooler Temperature Correlation

After a long key-off soak both the EGR temperature sensor and the charge-air cooler outlet temperature sensor must read approximately the same ambient temperature. The ECM compares them and detects an implausible delta. One of the sensors drifts, is wired wrong, or is exposed to a heat source the model does not know about.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number4 / F2

Possible causes

  • One sensor drifting outside tolerance high
  • Residual heat in the charge-air cooler after a hot soak medium

Symptoms

  • Check engine light on
  • Pinging or knocking under load
  • Power loss and hesitation
  • Possible rough idle
  • Failed emissions inspection (NOx)

Inspection / repair

  • Difficulty: medium
  • DIY: possible
  • Estimated cost: 80–400 €
  • Estimated time: 0.5–1.5 h
  • Component: egr temperature sensor
  • Component: cac outlet temperature sensor
  • MIL / check engine light
  • emissions-relevant

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