P2455 indicates that the PCM has detected a high voltage condition in the pressure sensor circuit for the diesel particulate filter (DPF). This usually means the sensor is reporting pressure that is higher than the calibrated maximum.
The sensor element can fail open, short, or become contaminated, causing it to output an abnormally high voltage.
Corrosion, broken wires, or a loose connector can create a high‑resistance path that the PCM interprets as a high sensor voltage.
A blocked or severely clogged filter can generate pressure beyond the sensor’s range, triggering the high‑circuit condition.
Using a sensor with an incompatible voltage range for the vehicle can cause the PCM to read a constant high voltage.
Only after all other possibilities are ruled out should a malfunctioning PCM be considered, as it is an uncommon cause of P2455.
It is possible but very unlikely. The PCM is usually the last component to be blamed after the sensor, wiring, and DPF have been verified.
Clearing the code only turns off the MIL. If the underlying issue (sensor, wiring, or pressure condition) remains, the code will return.
Not necessarily. The DPF itself is only a cause if it is severely clogged and creating excessive pressure. Cleaning or forced regeneration may resolve the condition before a replacement is needed.
Because the PCM monitors many sensor circuits, some technicians assume it is at fault. In real‑world experience, the PCM is rarely the cause of P2455; focus on the sensor, wiring, and DPF condition first.