P340D code meaning
Deactivation/Exhaust Valve Control Circuit Bank 2
Powertrain system Generic code P34xx codes Check engine light
What P340D means
P340D is the bank 2 version of the exhaust-side group circuit: the engine computer sees an electrical fault on the line that is supposed to disable the exhaust valves of the bank without cylinder 1. No manufacturer documents this code publicly. Separate exhaust control matters because a cylinder can only act as a gas spring if its exhaust valves stay shut too; a Ford patent shows how an exhaust valve that keeps opening can be detected from exhaust pressure. On known engines, though, intake and exhaust are switched together per cylinder, as with GM's DFM. CARB rules call for monitoring of outputs like this one. Related: P340C for bank 1, P340B for the bank 2 intake side, P341D for the function check. Deactivation stays off.
P340D 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 P340D
- Check engine lamp on
- Engine no longer drops cylinders at light load
Common causes of P340D
- PossibleDamaged wiring to the bank 2 exhaust deactivation actuator
- PossibleFaulty coil in the bank 2 exhaust actuator
- Less likelyOutput stage fault in the engine 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 P340D 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). |
| 0D | The exact fault in that area. |
What to do next
- Note P340D 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 P340D
What does P340D mean?
P340D means "Deactivation/Exhaust Valve Control Circuit Bank 2". P340D is the bank 2 version of the exhaust-side group circuit: the engine computer sees an electrical fault on the line that is supposed to disable the exhaust valves of the bank without cylinder 1. It is a generic code, so it means the same on every make.
Is it safe to drive with P340D?
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 P340D fail an emissions test?
Yes, it can. P340D 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 P340D 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 P340D clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.