P349A code meaning
Cylinder 3 Deactivation/Intake Valve Performance
Powertrain system Generic code P34xx codes Check engine light
What P349A means
P349A states that cylinder 3 kept its valves working while the engine computer had switched it off. GM picks this up on its L84 and L87 V8s through manifold pressure that stays too high during the skipped strokes, Type B after 22 failed checks out of 25. Not every stored P349A means a worn lifter. For the 2021 Tahoe, Suburban, Yukon and Escalade, GM explains (PIP5731, later bulletin 20-NA-204) that a voltage dip while cranking could make the ECM drop the deactivation outputs for one trip and log this code in history without a real defect; the cure is new ECM software and a road test with a warm engine at 30 to 45 mph. If it returns, the lifters and the solenoid of cylinder 3 need checking. P3418 covers the control side.
P349A 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 P349A
- Code stored in history with no noticeable concern
- Check engine lamp on if the fault is real
- Ticking noise or higher fuel use
Common causes of P349A
- PossibleVoltage dip at cranking disabled the outputs, ECM software outdated
- PossibleDeactivation lifter of cylinder 3 does not unlock
- PossibleLifter oil solenoid of cylinder 3 sticking
- Less likelyLow or aged oil slowing the switching
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
LifterValve trainCylinder deactivation solenoidECM
What each part of P349A 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). |
| 9A | The exact fault in that area. |
What to do next
- Note P349A 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 P349A
What does P349A mean?
P349A means "Cylinder 3 Deactivation/Intake Valve Performance". P349A states that cylinder 3 kept its valves working while the engine computer had switched it off. It is a generic code, so it means the same on every make.
Is it safe to drive with P349A?
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 P349A fail an emissions test?
Yes, it can. P349A 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 P349A to fix?
Difficulty: hard. A typical repair takes 0.5 to 14 hours of work. This is a job for a workshop.
Will P349A 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.