P0669 means the powertrain control module has detected an abnormally high signal from its own internal temperature sensor circuit. This indicates the module believes it is running hotter than expected, or the internal sensor circuit is reporting an out-of-range high voltage. The code may cause the module to enter a protective mode such as reduced power or limp-home operation.
The temperature-sensing circuit inside the control module may be reading incorrectly due to an internal open, short, or sensor failure. Because the sensor is built into the module, this is the most direct cause of the code.
Corroded, damaged, bent, or loose terminals at the control module connector can introduce resistance and produce a falsely high circuit reading.
If the module is mounted where it receives poor airflow, is blocked by debris, or is exposed to an external heat source, actual overheating can trigger the sensor.
Outdated or corrupted module calibration may misinterpret the internal sensor signal and set the code even when hardware is normal.
Rarely, a broader electrical failure inside the module causes false temperature-sensor readings; this should be considered only after wiring, heat, and software causes are ruled out.
Not automatically. The internal temperature sensor is part of the module, but wiring, connector, and overheating problems are common real causes. Many P0669 cases are resolved without replacing the PCM, so those should be checked first.
Short trips are usually possible, but the vehicle may enter limp mode or reduce power to protect itself. Have it diagnosed soon to avoid being stranded or causing further issues.
It means the voltage or signal value from the internal temperature sensor circuit is above the expected range. This can indicate an open circuit, a faulty sensor, or an actual overheating condition.
No, it is integrated into the control module. If the sensor circuit itself is confirmed faulty and all other causes are ruled out, the module typically requires replacement.