P340B code meaning
Deactivation/Intake Valve Control Circuit Bank 2
Powertrain system Generic code P34xx codes Check engine light
What P340B means
P340B mirrors P340A for bank 2, the bank that does not contain cylinder 1, so it only applies to V or boxer engines. It marks an electrical fault in a control circuit that switches the intake valves of that whole bank at once. No manufacturer documents this code publicly. The widespread V8 systems put the deactivating cylinders of bank 2, cylinders 4 and 6 on GM and Chrysler engines, on their own solenoids and report them as P3425 or P3441. Honda's VCM V6 watches bank 2 via a rocker arm oil pressure switch and stores P3497. CARB asks for circuit checks of such outputs. The bank 1 counterpart is P340A, the bank 2 exhaust circuit P340D, the function code P341B. Usually the only effects are the lamp and lost economy.
P340B 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 P340B
- Check engine lamp on
- Engine runs on all cylinders permanently
- Slightly higher fuel consumption
Common causes of P340B
- PossibleChafed, open or shorted wire to the bank 2 actuator
- PossibleOil or moisture in the bank 2 actuator connector
- PossibleDefective bank 2 intake deactivation actuator coil
- Less likelyEngine control module output stage fault
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 P340B 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). |
| 0B | The exact fault in that area. |
What to do next
- Note P340B 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 P340B
What does P340B mean?
P340B means "Deactivation/Intake Valve Control Circuit Bank 2". P340B mirrors P340A for bank 2, the bank that does not contain cylinder 1, so it only applies to V or boxer engines. It is a generic code, so it means the same on every make.
Is it safe to drive with P340B?
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 P340B fail an emissions test?
Yes, it can. P340B 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 P340B 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 P340B clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.