P042F code meaning
EGR A Control Stuck Closed
Powertrain system Generic code P04xx codes Check engine light
What P042F means
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 gasoline engines use position limits for 4 s; Ford diesels report both directions under P042E. With too little EGR, NOx rises, gasoline engines may knock and P0401 can follow.
P042F at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor1 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P042F
- Check engine light on (GM after one trip)
- Usually no driveability problems
- Possibly pinging (gasoline) or higher NOx
Common causes of P042F
- Most likelyValve coked or seized in the closed position
- PossibleActuator motor or gear weak or faulty
- PossiblePosition sensor or connector gives a wrong value
- Less likelyIcing in winter (temporary)
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
EGR valveEGR valve actuatorEGR valve position sensorEngine control module
What each part of P042F means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 4 | Area: auxiliary emission controls (catalytic converter, EGR, EVAP). |
| 2F | The exact fault in that area. |
What to do next
- Note P042F and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P042F
What does P042F mean?
P042F means "EGR A Control Stuck Closed". Exhaust gas recirculation (EGR) routes part of the exhaust back into the intake to lower combustion temperature and NOx. It is a generic code, so it means the same on every make.
Is it safe to drive with P042F?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P042F fail an emissions test?
Yes, it can. P042F is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P042F to fix?
Difficulty: medium. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will P042F clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.