P3427 indicates that the powertrain control module (PCM) has detected a low voltage condition in the control circuit for the cylinder 4 deactivation intake valve solenoid. This solenoid is part of the variable displacement system that deactivates cylinders to improve fuel economy, and a low circuit signal prevents proper operation.
The solenoid itself is the most common failure point. Internal short or open winding causes a low voltage reading in the control circuit.
The circuit between the PCM and the solenoid may be chafed, pinched, or exposed, creating a short to ground that pulls the voltage low.
Corrosion, bent pins, or loose terminals at the solenoid connector can increase resistance and cause a low voltage signal.
A weak battery or failing alternator can cause overall low voltage, triggering this code if the solenoid circuit is affected.
Although uncommon, an internal fault in the PCM can cause a low voltage reading on the solenoid control circuit. This should only be considered after all other possibilities are ruled out.
You may be able to drive, but the cylinder deactivation system will likely be disabled, reducing fuel economy. A misfire may also occur, which can damage the catalytic converter over time. It's best to diagnose and repair promptly.
Clearing the code will turn off the check engine light temporarily, but the underlying problem will cause the code to return. Use clearing only after the repair is completed.
No. The PCM is rarely the cause of this code. Most often the issue is a faulty solenoid, damaged wiring, or a poor connector. Replacing the PCM without proper diagnosis is unnecessary and costly.
Not immediately, but if the code is accompanied by a persistent misfire, unburned fuel can overheat and damage the catalytic converter. Address the code to avoid secondary damage.