Powertrain, shared range

P3434 Cylinder 5 Deactivation/Intake Valve Control Performance

Check engine lightOn

EmissionsRelevant

Drive cycleRequired

Limp modeNo

With P3434 the computer has found that cylinder 5 does not switch off or back on correctly, while the control circuit tests fine. No manufacturer documents this code publicly. GM's L84 runs the equivalent test under P349C: manifold pressure stays too high while cylinder 5 is commanded off, meaning its valves keep working. For 3.6 L V6 engines, GM bulletin 21-NA-036 describes the field picture: misfires on cylinder 5 (P0305), sometimes only after a reduced-cylinder phase, from oil leaking past the control valve or rockers that do not latch, and asks to check for a solenoid tip broken off in the bore. Wiring faults for this cylinder are P3433, P3435 and P3436.

Likely causes

Oil leaking past the cylinder 5 control valve seal

Switching rocker or lifter of cylinder 5 not latching

Solenoid tip broken off in the bore

Low or aged engine oil

Symptoms

Misfire on cylinder 5 (P0305)
Check engine lamp on
Shaking after reduced-cylinder operation

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, gsi.ext.gm.com, static.nhtsa.gov.