P3455 indicates that the powertrain control module has detected a low voltage condition in the exhaust valve control circuit for cylinder 7, meaning the valve is not opening or closing as commanded.
The electro‑hydraulic or electric actuator that moves the exhaust valve can fail electrically or mechanically, causing a low‑voltage reading.
Frayed wires, broken pins, or corrosion at the connector can create high resistance, resulting in a low voltage signal.
A poor ground path or a short to ground will pull the circuit voltage down, triggering the code.
The driver module that supplies power to the actuator may have an internal fault, limiting voltage to the valve.
Very rarely, the PCM itself can misinterpret the signal or have an internal fault, but this is the least common cause.
Resetting the code will only turn off the Check Engine Light temporarily. The underlying low‑voltage condition will cause the code to return until the fault is repaired.
No. In real‑world experience the PCM is the least likely cause. Wiring issues, a bad actuator, or a ground problem account for the vast majority of cases.
Not necessarily. A misfire can set a separate misfire code (P0307). P3455 specifically relates to the exhaust valve control circuit, which may cause a misfire but is a distinct issue.
A basic digital multimeter and a scan tool that can read live data and command actuator tests are sufficient for most diagnostics.