P042FEGR A Control Stuck Closed
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- 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.
- What you may notice
- Check engine light on (GM after one trip)
- Usually no driveability problems
- Possibly pinging (petrol) or higher NOx
- Likely causes
- LikelyValve coked or seized in the closed position
- PossibleActuator motor or gear weak or faulty
- PossiblePosition sensor or connector gives a wrong value
- RareIcing in winter (temporary)
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €150 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.