Powertrain, shared range

P3462 Cylinder 8 Exhaust Valve Control Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

With P3462 the ECM would be saying that the exhaust valve of cylinder 8 ignores deactivation commands even though nothing is wrong electrically. No manufacturer documents this code publicly. GM covers the exhaust side of cylinder 8 on the 2019 L84 with its own code P3190, Cylinder 8 Trapped High Pressure Exhaust Charge: if crankshaft jerk, normalized by engine speed, exceeds a load-dependent threshold while the cylinder is deactivated, the exhaust valve is judged not to have opened, and 66 failures in 100 samples set a Type B code. Ford patented the complementary check for an exhaust valve that keeps opening after deactivation, based on exhaust pressure. Symptoms range from vibration in reduced-cylinder mode to a misfire on cylinder 8 (P0308).

Likely causes

Exhaust lifter of cylinder 8 failing to relock in time
Oil supply to the lifter gallery insufficient
Exhaust-side control valve sticking

Symptoms

  • Check engine lamp on
  • Vibration while cylinders are deactivated
  • Misfire on cylinder 8 (P0308)

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–3,500
Time0–12 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

cylinder deactivation solenoidlifterengine oil

Related codes

P3461P3463P3464P3458P349FP0308

References: law.cornell.edu, gsi.ext.gm.com, patents.google.com.