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

P04DE

Cold Start EGR A Flow Excessive Detected

Same as P04DD with EGR flow above the cold-start target - typically valve sticking open during the cold phase or position sensor offset low.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number4 / DE

Possible causes

  • EGR valve A sticking open when cold 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: 250–1200 €
  • Estimated time: 1.5–4 h
  • Component: egr valve a
  • Component: egr position sensor a
  • 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