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

P02E9 Diesel Intake Air Flow A Position Sensor Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
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. P02E9 means the position signal is above its range – typically an open sensor ground or a signal shorted to voltage. GM's LML sets it above 4.72 V for 5 s in the first trip, newer GM diesels above 95–99 % of 5 V after two trips; Ford's diesels above 4.92 V for 3 s. On a fault the valve is switched off and the spring opens it: driving is usually little affected, but EGR control is restricted and filter regeneration may be blocked.

Likely causes

Sensor ground open
Signal shorted to voltage
Sensor faulty
Engine module

Symptoms

  • Check engine light on
  • Often no noticeable change
  • Filter regeneration does not run, soot load rises

Repair estimate

DifficultyMediumDIY possible
Parts and labour€50–500
Time0.5–2 h

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

Parts involved

diesel intake throttle position sensordiesel intake throttle valvesensor wiring

Related codes

P02E8P02E7P02E6P02EAP0123

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