P34A2 code meaning
Cylinder 11 Deactivation/Intake Valve Performance
Powertrain system Generic code P34xx codes Check engine light
What P34A2 means
P34A2 names a mechanical deactivation fault on cylinder 11: the valves continued to operate although the cylinder had been switched off. No manufacturer documents this code publicly. The nearest production example is the Active Cylinder Control that Mercedes fitted to the 5.8 l V12 of the CL 600 and S 600 from 2001; it idled one bank and uncoupled its exhaust valves by means of two solenoids; a stuck switching element there would produce exactly the fault this code describes. For eight-cylinder engines GM uses P3498 to P349F, judged by manifold pressure and stored as Type B after 22 failures in 25 checks. P3482 is the control-performance code for cylinder 11, and a misfire there would be P0311.
P34A2 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyWorkshop only
- Typical labor1 to 16 hours
- Clears after repairAfter a drive cycle
Symptoms of P34A2
- Check engine lamp on
- Rough running when one bank is shut down
- Higher fuel use
Common causes of P34A2
- Most likelyValve switching element of cylinder 11 jammed
- PossibleOil pressure supply to the switching parts disturbed
- Less likelyLow or degraded oil
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Valve trainLifterCylinder deactivation solenoidEngine oil
What each part of P34A2 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). |
| A2 | The exact fault in that area. |
What to do next
- Note P34A2 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 P34A2
What does P34A2 mean?
P34A2 means "Cylinder 11 Deactivation/Intake Valve Performance". P34A2 names a mechanical deactivation fault on cylinder 11: the valves continued to operate although the cylinder had been switched off. It is a generic code, so it means the same on every make.
Is it safe to drive with P34A2?
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 P34A2 fail an emissions test?
Yes, it can. P34A2 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 P34A2 to fix?
Difficulty: workshop only. A typical repair takes 1 to 16 hours of work. This is a job for a workshop.
Will P34A2 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.