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

P24F3

Reductant Tank Temperature/Fuel Temperature Correlation

After a long key-off soak the AdBlue/DEF tank temperature and the fuel tank temperature should read close to each other (both at ambient). The ECM detects an implausible spread, which usually means one of the two sensors drifts, is wired wrong, or has a heat source nearby that the plausibility model does not account for.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number4 / F3

Possible causes

  • One temperature sensor drifting outside tolerance high
  • Recently active reductant tank heater warming the tank above ambient medium

Symptoms

  • Check engine light or NOx warning on
  • AdBlue/DEF level or quality warning
  • Possible no-start countdown after ignore period
  • Failed emissions inspection (NOx)

Inspection / repair

  • Difficulty: medium
  • DIY: shop recommended
  • Estimated cost: 120–600 €
  • Estimated time: 0.5–2 h
  • Component: reductant tank temperature sensor
  • Component: fuel tank 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