P3454Cylinder 7 Exhaust Valve Control Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- P3454 covers an exhaust valve on cylinder 7 that does not switch as commanded, with no electrical fault on its control circuit. No manufacturer documents this code publicly. GM's own cylinder 7 check P318F on the 2019 L84 shows why the exhaust side matters: if the exhaust valve fails to open and release the burned gas, the trapped charge is compressed again, cylinder pressure climbs and the intake mechanism can be damaged on reactivation, so the ECM reacts at once (crankshaft jerk test, 66 of 100 samples, Type B). A Ford patent tackles the reverse problem, an exhaust valve still opening after deactivation, spotted through exhaust pressure. P3453, P3455 and P3456 are the electrical codes.
- What you may notice
- Check engine lamp on
- Hard knock or jolt when cylinder 7 is reactivated
- Possible misfire on cylinder 7 (P0307)
- Likely causes
- PossibleExhaust lifter of cylinder 7 stuck in the unlocked state
- PossibleOil pressure or oil quality inadequate for switching
- RareExhaust control valve slow or sticking
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €3,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.