Powertrain, shared range

P3422 Cylinder 3 Exhaust Valve Control Performance

Check engine lightOn

EmissionsRelevant

Drive cycleRequired

Limp modeNo

P3422 would apply if cylinder 3's exhaust valves disregard an order to stop or restart even though the wiring checks out. No manufacturer documents this code publicly. How such a fault can be spotted is shown in patents: Ford patented a way to catch an exhaust valve still lifting after shutdown by its mark in the exhaust pressure trace; the engine then brings the cylinder back, blocks further deactivation and may store a code. A Delphi patent does the same for the intake side by timing pressure pulses against crank angle. GM folds both valves of cylinder 3 into one mechanical check, P349A. A leaking exhaust valve pumps air through the cold cylinder, which upsets fuel trim and can cause a misfire count on cylinder 3.

Likely causes

Exhaust-side switching lifter or rocker of cylinder 3 stuck

Oil level or quality outside specification

Restricted oil passage to the exhaust switching element

Symptoms

Uneven running in reduced-cylinder mode
Fuel trim or misfire codes alongside
Check engine lamp on

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

References: law.cornell.edu, patents.google.com, patents.google.com, static.nhtsa.gov.