Paccar

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).

PACCAR MX (2004 Emissions) Fault Code: P2183 Engine Coolant Temperature – Data Erratic, Intermittent, or Incorrect

SET CONDITIONS:
The PCI ECU (D420) detects that the measured coolant temperature differs by more than 20°C [68°F] from the expected coolant temperature for more than 45 seconds.

DIAGNOSTIC CONDITION:
This diagnostic runs:
1. 150 seconds after an engine start and
2. When the ambient temperature is above -8°C [17°F] and
3. When the calculated coolant temperature is below 65°C [149°F] or above 85°C [185°F] and
4. 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. To validate the repair, drive the vehicle until the coolant temperature is at least 70°C [158°F] in normal driving conditions. This activity is best conducted with a loaded vehicle/trailer.

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. Faulty thermostat
2. Excessive heat drawn from the cooling system
3. Coolant temperature sensor deviation

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

PACCAR MX (2004 Emissions) Fault Code: P2199 Inlet Air Temperature Before Compressor – Data Erratic, Intermittent or Incorrect, at Ignition On

SET CONDITIONS:
The PCI ECU (D420) detects that the measured temperature reading of the humidity sensor differs more than 3°C [5.4°F] from the average of other temperature sensor readings on the engine for more than 5 seconds (after the ignition has been keyed off for at least 8 hours).

DIAGNOSTIC CONDITION:
This diagnostic runs:
1. When the ignition has been keyed off continuously for at least 8 hours
2. When the difference between the coolant temperature and ambient temperature is less than 15°C [59°F]
3. When the ambient temperature is more than -20°C [-4°F]

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:
Humidity sensor deviation

ADDITIONAL INFORMATION:
1. For this diagnostic, the temperature reading of the humidity sensor is compared with an average of other temperature sensors on the engine after the ignition has been keyed off for at least 8 hours.

2. The humidity sensor (F852) is a smart sensor that communicates with the PCI ECU via E-CAN. The sensor measures the following three properties of the drawn in precompressor (VTG turbo charger) air in the inlet air pipe:
– Relative humidity
– Pressure
– Temperature

PACCAR MX (2004 Emissions) Fault Code: P2226 Internal ECU Ambient Pressure – Data Erratic, Intermittent or Incorrect, at Ignition On

SET CONDITIONS:
The PCI ECU (D420) detects that the measured ambient pressure differs by more than 0.06 bar [0.87 psi] from the average readings of other pressure sensors in the engine/aftertreatment system for more than 5 seconds.

DIAGNOSTIC CONDITION:
This diagnostic runs:
1. When the ignition is on and the engine is not running and
2. When ambient temperature is above -20°C [-4°F]

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:
Faulty pressure sensor, internally in ECU.

ADDITIONAL INFORMATION:
The PCI ECU has an internal ambient pressure sensor in the housing. The ambient pressure sensor is not serviceable.

For this diagnostic, the ambient pressure sensor reading is compared with the average readings from the pre-compressor pressure (humidity sensor (F852)), boost pressure sensor (F802) and DPF pressure sensor (F837).

PACCAR MX (2004 Emissions) Fault Code: P222C Internal ECU Ambient Pressure – Internal Error

SET CONDITIONS:
The PCI ECU (D420) detects that the internal ambient pressure sensor is faulty.

DIAGNOSTIC CONDITION:
This diagnostic runs continuously when the ignition is 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:
Faulty pressure sensor, internally in ECU

ADDITIONAL INFORMATION:
The PCI ECU has an internal ambient pressure sensor in the housing. The ambient pressure sensor is not serviceable.

PACCAR MX (2004 Emissions) Fault Code: P2238 Lambda – Current Too Low on ECU (D420) Pin (C45)

SET CONDITIONS:
The PCI ECU (D420) detects a lower current than expected in the measuring circuit of the lambda sensor.

DIAGNOSTIC CONDITION:
The diagnostic runs continuously when the ignition is keyed on.

RESET CONDITION:
The DTC changes to inactive after the diagnostic runs and passes.

POSSIBLE CAUSES:
1. Lambda sensor wiring issue
2. Lambda sensor failure