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

P241F

EGR Cooler B Efficiency Below Threshold

The temperature drop across EGR cooler B is below the calibrated threshold - cooler is fouled with soot, has internal scaling, or coolant flow is restricted. Recirculated gas reaches the intake hotter than designed, increasing NOx and combustion temperatures.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number4 / 1F

Possible causes

  • Cooler fouled with soot or scaled high

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: shop recommended
  • Estimated cost: 400–1500 €
  • Estimated time: 2–5 h
  • Component: egr cooler b
  • 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