Powertrain, generic · Auxiliary emission controls

P042F EGR A Control Stuck Closed

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

Exhaust gas recirculation (EGR) routes part of the exhaust back into the intake to lower combustion temperature and NOx. P042F means EGR valve A does not follow the opening command: its actual position stays more closed than commanded although the actuator works with high opening duty. GM's diesels of 2016/17 set it after about 1–8 s with MIL on the first trip; a GM bulletin covers it on the 2017 Cruze diesel. Ford petrol engines use position limits for 4 s; Ford diesels report both directions under P042E. With too little EGR, NOx rises, petrol engines may knock and P0401 can follow.

Likely causes

Valve coked or seized in the closed position
Actuator motor or gear weak or faulty
Position sensor or connector gives a wrong value
Icing in winter (temporary)

Symptoms

  • Check engine light on (GM after one trip)
  • Usually no driveability problems
  • Possibly pinging (petrol) or higher NOx

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€150–900
Time1–4 h

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

Parts involved

egr valveegr valve actuatoregr valve position sensorengine control module

Related codes

P042EP0401P0404P0405P045F

References: gsi.ext.gm.com, gsi.ext.gm.com, fordservicecontent.com, static.nhtsa.gov.