P3423 code meaning
Cylinder 3 Exhaust Valve Control Circuit Low
Powertrain system Generic code P34xx codes Check engine light
What P3423 means
P3423 points to a grounded control wire at a dedicated cylinder 3 exhaust actuator. No manufacturer documents this code publicly, and NHTSA's 2025 look at GM's DFM engines shows why: each cylinder has just one lifter oil solenoid, and it feeds both lifters, intake and exhaust, so there is no separate exhaust output that could fail. For that same solenoid on cylinder 3, GM's L84 table flags a resistance to ground under half an ohm at rest and files it as P3419. The 2007 Displacement on Demand application likewise lists only one solenoid circuit for cylinder 3. Any design with its own exhaust output would fall under the CARB duty to detect shorts. Effect: warning lamp, cylinder 3 stays active.
P3423 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P3423
- Check engine lamp on
- No switch to reduced-cylinder operation
Common causes of P3423
- PossibleExhaust actuator wire of cylinder 3 shorted to engine ground
- PossibleActuator winding shorted to its housing
- Less likelyFaulty output stage in the control module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Cylinder deactivation solenoidWiring harnessECM
What each part of P3423 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). |
| 23 | The exact fault in that area. |
What to do next
- Note P3423 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 P3423
What does P3423 mean?
P3423 means "Cylinder 3 Exhaust Valve Control Circuit Low". P3423 points to a grounded control wire at a dedicated cylinder 3 exhaust actuator. It is a generic code, so it means the same on every make.
Is it safe to drive with P3423?
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 P3423 fail an emissions test?
Yes, it can. P3423 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 P3423 to fix?
Difficulty: medium. A typical repair takes 0.5 to 4 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P3423 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.