PACCAR MX (2004 Emissions) Fault Code: P0669 Internal ECU Temperature – Internal Error

PACCAR MX (2004 Emissions) Fault Code: P0669 Internal ECU Temperature – Internal Error

SET CONDITIONS:
The temperature measured by the internal ECU temperature sensor is out of range high.

DIAGNOSTIC CONDITION:
This diagnostic runs continuously when the ignition is on.

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
This DTC changes to inactive when the fault is no longer detected.

REPAIR VERIFICATION:
1. Clear all DTCs.
2. Test drive or operate the vehicle to meet the diagnostic conditions and set conditions.
3. Did the DTC come back?
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
Faulty temperature sensor, internally in ECU. Clear the fault with the diagnostic service tool. If the fault reoccurs after ignition on, replace the ECU.

ADDITIONAL INFORMATION:
The PCI ECU temperature is monitored by an internal temperature sensor in the printed circuit board. This temperature sensor is not serviceable.