P3493 code meaning
Cylinder 12 Exhaust Valve Control Circuit/Open
Powertrain system Generic code P34xx codes Check engine light
What P3493 means
P3493 applies to a separately controlled exhaust valve on cylinder 12 and reports that its actuator circuit is open. No manufacturer documents this code publicly; J2012 reserves the codes for cylinders 9 to 12 for engines with more than eight cylinders. Bentley's W12 and the Lamborghini Aventador V12 shut off banks; Bentley explicitly keeps the valves operating, and Lamborghini describes only the switch to six cylinders below 135 km/h. A GM patent treats the exhaust valves as a step of their own, stopping them before the intake valves, while GM's later production design drives both valves of a cylinder from one solenoid. An open exhaust circuit on cylinder 12 therefore points to a rare design. P3495 and P3496 are the short-circuit codes, P3494 the function, P3489 the intake side.
P3493 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 P3493
- Check engine lamp on
- Partial-cylinder operation unavailable
Common causes of P3493
- PossibleWire to the cylinder 12 exhaust actuator open
- PossibleCoil of the cylinder 12 exhaust actuator interrupted
- PossibleExhaust actuator connector corroded
- Less likelyControl module output failed
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 P3493 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). |
| 93 | The exact fault in that area. |
What to do next
- Note P3493 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 P3493
What does P3493 mean?
P3493 means "Cylinder 12 Exhaust Valve Control Circuit/Open". P3493 applies to a separately controlled exhaust valve on cylinder 12 and reports that its actuator circuit is open. It is a generic code, so it means the same on every make.
Is it safe to drive with P3493?
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 P3493 fail an emissions test?
Yes, it can. P3493 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 P3493 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 P3493 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.