Powertrain, generic · Fuel and air metering (injector circuit)

P02E4 Diesel Intake Air Flow A Control Stuck Open

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

The diesel intake air flow valve A is the throttle flap ahead of the intake manifold of a diesel engine: it creates the vacuum needed for high EGR rates, lowers airflow to heat the particulate filter and catalyst during regeneration and closes at switch-off against run-on shaking. A spring holds it open when unpowered; an electric motor positions it, with a position sensor reporting back. P02E4 means the valve stays more open than commanded, so the EGR rate and regeneration heating cannot be achieved. GM sets it when the valve is over 8 % more open than commanded although the motor pushes at more than 80 % duty, for about 4 s, with the warning light in the first trip; Ford's diesels at more than 15 % deviation for 25 s, also during the cold-start strategy. Driving is barely affected, but NOx and soot rise.

Likely causes

Coking or oil carbon preventing closing
Return spring or gear faulty, flap loose on the shaft
Motor too weak (wear)
Foreign object or ice

Symptoms

  • Check engine light on
  • Regeneration aborts, soot load rises
  • Shaking at switch-off, little loss of power

Repair estimate

DifficultyMediumDIY possible
Parts and labour€50–600
Time0.5–2.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

diesel intake throttle valvethrottle valve motoractuator wiring

Related codes

P02E5P02E1P2394P02FAP0401

References: law.cornell.edu, gsi.ext.gm.com, fordservicecontent.com, ms-motorservice.com.