Probable Causes
The probable root causes are listed in order below:
• Normal operation
• Fuel supply
• Atmospheric pressure circuit
• Coolant temperature circuit
• Electronic unit injector
• Combustion problem
Recommended Actions
Perform the following diagnostic procedures in order:
1. Be aware of normal operating conditions.
Cold outside temperatures can affect the production of white smoke.
2. Check the fuel supply.
a. Monitor the exhaust for smoke while the engine is being cranked.
If no smoke is present, there may be a problem with the fuel quality or there may be a problem with the fuel supply.
b. Check the fuel quality. Refer to Testing and Adjusting, “Fuel Quality – Test”. Also refer to the Truck Performance and Driveability Diagnostic Guide, LEBT3477.
c. Check the fuel pressure. Refer to Testing and Adjusting, “Fuel System Pressure – Test”.
d. Ensure that the fuel system has been primed.
Refer to Testing and Adjusting, “Fuel System – Prime”.
e. Check for fuel supply lines that are restricted.
f. Check the fuel filters.
g. If the temperature is below 0 C (32 F), check for solidified fuel (wax).
h. Check for air in the fuel system. Refer to Testing and Adjusting, “Air in Fuel – Test”.
3. Check the atmospheric pressure circuit.
a. Connect the electronic service tool to the data link connector.
b. Check for diagnostic codes that are related to the atmospheric pressure sensor.
c. Monitor the status of the atmospheric pressure sensor on the status screen. Compare the
value for the atmospheric pressure on the status screen to the actual atmospheric pressure.
d. If the atmospheric pressure on the status screen is at least 7 kPa (1 psi) greater than the actual atmospheric pressure, inspect the crankcase breather for restrictions.
e. Remove a valve cover.
f. Recheck the atmospheric pressure on the status screen.
g. If removing the crankcase breather solves the problem, replace the crankcase breather.
h. If the crankcase breather is not restricted or removing the valve cover does not eliminate the problem, proceed to Step 4.
4. Check the coolant temperature circuit.
a. Check for diagnostic codes that are related to the coolant temperature sensor.
b. Monitor the status of the coolant temperature sensor on the status screen. If an active diagnostic code is detected, refer to Troubleshooting, “Engine Temperature Sensor Open or Short Circuit – Test”.
5. Check the electronic unit injector.
a. Ensure that the front valve cover connector and the rear valve cover connector are fully connected and ensure that the valve cover connectors are free of corrosion.
b. Ensure that the J2/P2 ECM connector is fully connected and ensure that the ECM connector is free of corrosion.
c. Use the “Cylinder Cutout Test”. Access the “Cylinder Cutout Test” from the “Diagnostics Test” under the “Diagnostics” menu. Run the “Cylinder Cutout Test” in order to disable each cylinder. Disabling each cylinder allows the technician to isolate the misfiring cylinders.
If the misfiring cylinder can be isolated to a specific cylinder, refer to Troubleshooting,
“Injector Solenoid Circuit – Test”.
6. Check for combustion problems.
Examples of combustion problems are shown in the following list:
• Outside temperatures are too cold.
• Mechanical problem
