Faulty deactivation/exhaust valve solenoid or actuator; Damaged or corroded wiring harness or connector at the valve; Open or shorted control circuit between the PCM and the valve; Failed PCM driver for the valve control circuit; Internal mechanical binding of the valve assembly; Oil sludge or debris obstructing the valve solenoid passages

DTC codes / P34xx · Auxiliary emission controls / P340D

P340DDeactivation/Exhaust Valve Control Circuit Bank 2

Q: What does code P340D mean?

Deactivation/Exhaust Valve Control Circuit Bank 2. P340D indicates that the powertrain control module (PCM) has detected an electrical fault in the control circuit for the bank 2 deactivation or exhaust valve, which is used to manage cylinder deactivation or exhaust flow. The PCM monitors the circuit for expected voltage or current and sets this code when the signal is out of range, indicating an open, short, or component failure.

P340D indicates that the powertrain control module (PCM) has detected an electrical fault in the control circuit for the bank 2 deactivation or exhaust valve, which is used to manage cylinder deactivation or exhaust flow. The PCM monitors the circuit for expected voltage or current and sets this code when the signal is out of range, indicating an open, short, or component failure.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaAuxiliary emission controls

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Rough idle or misfire-like shudder, especially when the engine transitions between full and reduced displacement
Reduced engine power or a limp-home mode in some vehicles
Audible ticking or tapping from the valve area during activation
Poor fuel economy if the valve remains stuck in one position
In rare cases, a noticeable exhaust leak sound or increased exhaust noise

Common causes, most likely first

Faulty deactivation/exhaust valve solenoid or actuator
Damaged or corroded wiring harness or connector at the valve
Open or shorted control circuit between the PCM and the valve
Failed PCM driver for the valve control circuit
Internal mechanical binding of the valve assembly
Oil sludge or debris obstructing the valve solenoid passages

How to diagnose and fix it

Perform a visual inspection of the valve, connector, and wiring for damage or corrosion
Use a scan tool to command the valve on and off and listen for activation
Measure resistance and voltage at the valve solenoid and compare to manufacturer specifications
Check continuity and shorts in the control circuit from the PCM to the valve
Test the PCM output signal with a lab scope or bidirectional scan tool
Replace the faulty valve solenoid or actuator if electrically defective
Repair or replace damaged wiring or connectors, then clear codes and verify operation

Don't overlook circuit integrity checks

A common oversight is replacing the valve solenoid without first checking the wiring harness for chafing or corrosion, which often mimics a failed solenoid.
The code can be set by a mechanical binding issue that prevents the valve from moving freely, so electrical tests alone may not reveal the root cause.
Some vehicles use the same circuit for multiple functions, so a fault in a related system can trigger P340D even if the valve itself is fine.
Intermittent faults may only appear under specific conditions such as cold starts or high load, making a wiggle test of the harness essential.
A failed PCM driver is rare but possible; always rule out simpler causes before condemning the computer.

Can I keep driving with P340D?

You can usually drive the vehicle with this code, but avoid heavy acceleration or towing until it is repaired, as the engine may enter a reduced-power mode or suffer from poor fuel economy and increased emissions.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.