PACCAR MX (2004 Emissions) Fault Code: P1298 Engine Oil Temperature – Data Valid but Too High, Moderately Severe

PACCAR MX (2004 Emissions) Fault Code: P1298 Engine Oil Temperature – Data Valid but Too High, Moderately Severe

SET CONDITIONS:
The PCI ECU (D420) detects that measured oil temperature is higher than 125?C [257?F] for more than 60 seconds.

DIAGNOSTIC CONDITION:
This diagnostic runs continuously after ignition is keyed 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:
1. Malfunction on thermostat in oil module
2. Blocked oil cooler
3. Restriction in the cooling circuit to the oil cooler in the engine block/oil module

ADDITIONAL INFORMATION:
1. The oil temperature is monitored by the oil temperature sensor (F808).
2. The yellow warning is activated on the driver’s display.