PACCAR MX (2004 Emissions) Fault Code: P1127 Intercooler Temperature – Data Valid but Too High, Moderately Severe

PACCAR MX (2004 Emissions) Fault Code: P1127 Intercooler Temperature – Data Valid but Too High, Moderately Severe

SET CONDITIONS:
The PCI ECU (D420) detects that the intercooler outlet temperature is more than 95?C [203?F] for more than 60 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
2. Faulty engine cooling fan
3. Intercooler temperature sensor deviation

ADDITIONAL INFORMATION:
The intercooler outlet temperature is measured before the EGR mixer by the intercooler temperature sensor (F750).