P3446Cylinder 6 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
- P3446 stands for an exhaust valve on cylinder 6 that does not follow a deactivation or reactivation command although its circuit is intact. No manufacturer documents this code publicly. GM watches a closely related failure under a code of its own: on the 2019 L84, P318E (Cylinder 6 Trapped High Pressure Exhaust Charge) looks for an exhaust valve that fails to open and let the burned gas out, recognised by crankshaft jerk in 66 of 100 samples, Type B, with immediate protective action. A Ford patent covers the opposite case, an exhaust valve that keeps opening after shut-off, detected from exhaust pressure. The electrical codes for this exhaust channel are P3445, P3447 and P3448.
- What you may notice
- Check engine lamp on
- Knock-like noise or vibration when the cylinder is switched back on
- Possible misfire on cylinder 6 (P0306)
- Likely causes
- PossibleExhaust lifter of cylinder 6 switching late or not at all
- PossibleOil pressure too low for reliable switching
- RareExhaust control valve 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.