The engine computer's internal temperature sensor is reading too high, like a thermometer stuck in the sun. This prevents the PCM from accurately managing engine functions that depend on its own operating temperature.
The PCM monitors its own internal die temperature using an on-chip thermistor to adjust processing speed and fuel delivery calibration. When the voltage signal exceeds the upper threshold, it indicates either excessive heat buildup or a sensor circuit malfunction. The ECU uses this reading to protect itself from thermal damage.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| PCM Temperature Sensor Voltage | 0.5–2.5V (roughly 40–120°C) | >2.5V (excessive temperature signal) |
| PCM Die Temperature | <130°C operating safe zone | >150°C (triggers fault code) |