Powertrain, shared range

P3499 Cylinder 2 Deactivation/Intake Valve Performance

Check engine lightOn

EmissionsRelevant

Drive cycleRequired

Limp modeNo

P3499 reports that cylinder 2 did not stop exchanging gas when told to deactivate. On GM's DFM V8s (L84, L87) one oil solenoid in the lifter valley feeds both lifters of the cylinder; oil pressure pushes spring-loaded pins inward which lets the outer lifter shell ride the cam while the valve remains closed. If those pins stay engaged, the engine computer sees manifold pressure that is too high during the skipped events and, after 22 of 25 failed opportunities, stores this Type B code. GM's 2019 Silverado and Sierra information PIP5584 names a faulty oil control solenoid as one cause. The electrical side of cylinder 2 has its own codes (P3409, P3411, P3412), and the control-performance code is P3410. Expect a lamp and lost economy.

Likely causes

Locking pins in the cylinder 2 lifters do not retract

Lifter oil solenoid of cylinder 2 not delivering oil pressure

Low, aerated or degraded oil

Code stored without a real fault, ECM software update needed

Symptoms

Check engine lamp on
Higher fuel consumption because cylinder 2 is no longer skipped
Ticking from the lifter area

Repair estimate

DifficultyHardWorkshop job

Parts and labour€100–4,500

Time0–14 h

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

Parts involved

liftervalve traincylinder deactivation solenoidengine oil

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