PACCAR MX (2004 Emissions) Fault Code: P1115 Engine Coolant Temperature – Data Valid but Too High, Moderately Severe

PACCAR MX (2004 Emissions) Fault Code: P1115 Engine Coolant Temperature – Data Valid but Too High, Moderately Severe

SET CONDITIONS:
The PCI ECU (D420) detects that measured coolant temperature is more than 110?C [230?F] for more than 10 s.

DIAGNOSTIC CONDITION:
This diagnosis runs continuously when the ignition is keyed ON.

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
This DTC changes to INACTIVE after the diagnosis runs and passes.

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. Coolant level too low
2. Contaminated radiator
3. Blocked thermostat
4. Coolant temperature sensor deviation
5. Faulty engine cooling fan
6. Faulty engine coolant pump

ADDITIONAL INFORMATION:
1. The engine coolant temperature is monitored by the coolant temperature sensor (F566).
2. A yellow warning is active on the driver’s display.