PACCAR MX (2004 Emissions) Fault Code: P2181 Engine Coolant Temperature – Does not Match Engine Operating Conditions

PACCAR MX (2004 Emissions) Fault Code: P2181 Engine Coolant Temperature – Does not Match Engine Operating Conditions

SET CONDITIONS:
The PCI ECU (D420) detects that the measured coolant temperature differs by more than 10°C [50°F] from the expected coolant temperature for more than 30 seconds.

DIAGNOSTIC CONDITION:
This diagnostic runs:
1. 150 seconds after an engine start
2. When the ambient temperature is between -8 and 40°C [17 and 104°F]
3. When the engine mode is DOC heating or DPF regeneration or SCR heating or SCR high efficiency or standard or protection

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? (Can be pending, inactive or active)
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
1. Blocked open thermostat
2. Excessive heat drawn from the cooling system

ADDITIONAL INFORMATION:
The engine coolant temperature is monitored by the coolant temperature sensor (F566).