PACCAR MX (2004 Emissions) Fault Code: P0127 Intercooler Temperature – Data Valid but Too High, Most Severe

PACCAR MX (2004 Emissions) Fault Code: P0127 Intercooler Temperature – Data Valid but Too High, Most Severe

SET CONDITIONS:
The PCI ECU (D420) detects that the intercooler outlet temperature is more than 100°C [212°F] for more than 30 seconds.

DIAGNOSTIC CONDITION:
This diagnostic runs 300 seconds after the engine is started.

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:
1. Restricted air flow through intercooler/radiator. This can be caused by:
– A fouled bug screen
– A fouled intercooler
– The use of a winter front at temperatures above 4°C [40°F]
– The use of an aftermarket winter front with excessive airflow restriction through
the intercooler/radiator.
2. Faulty engine cooling fan
3. Intercooler temperature sensor deviation

ADDITIONAL INFORMATION:
1. The intercooler outlet temperature is measured before the EGR mixer temperature by the intercooler temperature sensor (F750).
2. Engine torque is reduced when this DTC is active.