P3499 code meaning
Cylinder 2 Deactivation/Intake Valve Performance
Powertrain system Generic code P34xx codes Check engine light
What P3499 means
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.
P3499 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyHard
- Typical labor0.5 to 14 hours
- Clears after repairAfter a drive cycle
Symptoms of P3499
- Check engine lamp on
- Higher fuel consumption because cylinder 2 is no longer skipped
- Ticking from the lifter area
Common causes of P3499
- Most likelyLocking pins in the cylinder 2 lifters do not retract
- PossibleLifter oil solenoid of cylinder 2 not delivering oil pressure
- PossibleLow, aerated or degraded oil
- Less likelyCode stored without a real fault, ECM software update needed
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
LifterValve trainCylinder deactivation solenoidEngine oil
What each part of P3499 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 3 | Mixed range: generic and manufacturer-specific codes. |
| 4 | Area: auxiliary emission controls (catalytic converter, EGR, EVAP). |
| 99 | The exact fault in that area. |
What to do next
- Note P3499 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P3499
What does P3499 mean?
P3499 means "Cylinder 2 Deactivation/Intake Valve Performance". P3499 reports that cylinder 2 did not stop exchanging gas when told to deactivate. It is a generic code, so it means the same on every make.
Is it safe to drive with P3499?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P3499 fail an emissions test?
Yes, it can. P3499 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P3499 to fix?
Difficulty: hard. A typical repair takes 0.5 to 14 hours of work. This is a job for a workshop.
Will P3499 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.