P3466 code meaning
Cylinder 9 Deactivation/Intake Valve Control Performance
Powertrain system Generic code P34xx codes Check engine light
What P3466 means
P3466 is the plausibility test for cylinder 9: its actuator circuit is electrically sound, yet the cylinder fails to change state when the engine computer commands it. No manufacturer documents this code publicly; J2012 reserves the codes for cylinders 9 to 12 for engines with more than eight cylinders. In valve-based systems the switching happens hydraulically; NHTSA's account of GM's design describes oil pressure moving locking pins inside the lifter. The Mercedes M137 V12, whose shut-off system relied on a solenoid pack and oil pressure tubes, is known for trouble with exactly those parts, exactly the kind of fault this code targets. Bank-switching V10 and W12 engines from Audi and Bentley leave the valves running and have nothing comparable to check. P3465, P3467 and P3468 are the electrical faults of cylinder 9.
P3466 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyHard
- Typical labor0.5 to 12 hours
- Clears after repairAfter a drive cycle
Symptoms of P3466
- Check engine lamp on
- Misfire count on cylinder 9 (P0309)
- Rough running while switching between full and partial mode
Common causes of P3466
- Most likelyOil level, pressure or quality too poor to switch cylinder 9
- PossibleLeak at the oil tubes or solenoid pack feeding cylinder 9
- PossibleSwitching lifter of cylinder 9 sticking
- Less likelySolenoid valve slow or sticking mechanically
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Cylinder deactivation solenoidLifterEngine oil
What each part of P3466 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). |
| 66 | The exact fault in that area. |
What to do next
- Note P3466 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 P3466
What does P3466 mean?
P3466 means "Cylinder 9 Deactivation/Intake Valve Control Performance". P3466 is the plausibility test for cylinder 9: its actuator circuit is electrically sound, yet the cylinder fails to change state when the engine computer commands it. It is a generic code, so it means the same on every make.
Is it safe to drive with P3466?
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 P3466 fail an emissions test?
Yes, it can. P3466 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 P3466 to fix?
Difficulty: hard. A typical repair takes 0.5 to 12 hours of work. This is a job for a workshop.
Will P3466 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.