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

P26FC

EGR Cooler Bypass Control Stuck Closed Bank 2

The EGR cooler bypass valve on bank 2 is stuck in the closed position. EGR gas always passes through the cooler, slowing engine warm-up and degrading cold-start emissions.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number6 / FC

Possible causes

  • Valve flap seized closed by soot high
  • Actuator linkage jammed in closed position medium
  • Carbon or debris buildup preventing free movement low

Symptoms

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

Inspection / repair

  • Difficulty: hard
  • DIY: shop recommended
  • Estimated cost: 250–1800 €
  • Estimated time: 1.5–5.5 h
  • Component: egr cooler bypass valve b2
  • Component: bypass actuator
  • 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