P23E5 code meaning
EGR C Control Stuck Open
Powertrain system Generic code P23xx codes Check engine light
What P23E5 means
P23E5 means EGR valve C stays open although it is commanded closed. The 2018 GM diesel calibration decides the A-side code P042E like this: once the driver is switched off, the return spring should bring the valve to its closed default within 2 s; if the measured position is still above 5 % after that, the code sets at once as Type A, MIL on the first trip. Comparable logic would suit valve C. Too much exhaust gas at idle or under load causes rough running, misfire, stalling and, on diesels, smoke, which is why such faults are rated urgently. Carbon build-up holding the flap open is the usual cause; a broken spring or jammed linkage are others. No manufacturer documents P23E5 publicly. Stuck closed: P23E6, excessive flow: P23E8.
P23E5 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 4 hours
- Clears after repairAfter a drive cycle
Symptoms of P23E5
- Rough idle or stalling
- Misfire and lack of power
- Smoke on diesel engines
- Warning lamp on the first trip
Common causes of P23E5
- Most likelyCarbon deposits holding valve C open
- PossibleBroken return spring in valve C
- Less likelyJammed shaft or linkage
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
EGR valve c
What each part of P23E5 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 3 | Area: ignition system or misfire. |
| E5 | The exact fault in that area. |
What to do next
- Note P23E5 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 P23E5
What does P23E5 mean?
P23E5 means "EGR C Control Stuck Open". P23E5 means EGR valve C stays open although it is commanded closed. It is a generic code, so it means the same on every make.
Is it safe to drive with P23E5?
Drive gently and only to a workshop. With P23E5 the car can go into limp mode (reduced power) to protect itself.
Will P23E5 fail an emissions test?
Yes, it can. P23E5 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 P23E5 to fix?
Difficulty: medium. A typical repair takes 0.5 to 4 hours of work. This is a job for a workshop.
Will P23E5 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.