P3424Cylinder 3 Exhaust Valve Control Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P3424 closes the cylinder 3 block and stands for an exhaust actuator control line that is held at supply voltage. No manufacturer documents this code publicly. The L84 from GM shows how far one shared solenoid can be monitored without it: for cylinder 3 the ECM checks a low-side driver under P3417, P3419 and P3420 and a high-side driver under extra codes of its own, yet none of them is exhaust-only. A GM patent application explains why: one hydraulic switching valve per cylinder pair serves intake and exhaust, the order being set by the cam lobes. The nearest documented test is the one behind P3420, in which a supply connection of less than half an ohm, seen with the output active, is judged a short. A driver would notice only the lamp.
- What you may notice
- Check engine lamp on
- Engine runs on all cylinders permanently
- Likely causes
- PossibleExhaust actuator wire chafed against a supply line
- PossibleShorted turns in the exhaust actuator of cylinder 3
- RareEngine control module output fault
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €60 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.