- Selected engine rating parameters
- Cold Mode
- Active engine derate
- Electrical connections to the ECM
- Throttle signal
- Circuit for electronic unit injectors
- Fuel supply
- Boost pressure sensor
- Air inlet and exhaust system
Note: If the problem only occurs under certain conditions, test the engine under those conditions. Examples of certain conditions are high rpm, full load and engine operating temperature. Troubleshooting the symptoms under other conditions can give misleading results.
Selected Engine Rating Parameters
Verify that the complaint is not due to a normal operation such as a programmed parameter. Connect the electronic service tool and verify that the parameters are programmed correctly.
Verify that the injector codes have been programmed.
- Use the electronic service tool to verify that the engine has exited Cold Mode. Cold Mode operation may cause the engine to run rough and engine power may be limited.
- Observe the status of the coolant temperature on the electronic service tool. Verify that the reading is valid.
Use the electronic service tool to check for logged engine derates. Refer to the section Troubleshooting, "Troubleshooting with an Event Code" for the specific events that are applicable to this application. A derate status flag will appear on the electronic service tool if an active engine derate is occurring.
Electrical Connections to the ECM
Check the associated wiring for damage, abrasion, corrosion or incorrect attachment on the following connectors: J1/P1 and J2/P2 ECM connectors, J61/P61 Customer Connector and J403/P403 Primary Throttle Position Sensor connector and J404/P404 Secondary Throttle Position Sensor connector. Refer to Troubleshooting, "Electrical Connectors-Inspect" for additional information.
Connect an Electronic Service Tool to the service tool connector. Turn the keyswitch to the ON with the engine OFF.
Monitor the throttle position from low idle to full throttle. The duty cycle should be between 5 and 10 percent at low idle. The duty cycle will increase to 90 to 95 percent at full throttle. Refer to Troubleshooting, "Throttle Position Sensor Circuit - Test" for additional information if the change in the throttle position is erratic or if the change in the throttle position is out of the specified range.
Circuit for the Electronic Unit Injector
Inspect the J2/P2 ECM connector and the J300/P300 Unit Injector connector for proper connections. Refer to Troubleshooting, " Electrical Connectors - Inspect". Connect an Electronic Service Tool and cut out each cylinder in order to isolate the misfiring cylinder or cylinders. If the results are inconclusive, shut off half of the cylinders and repeat the cylinder cutout test on the active cylinders that are remaining in order to locate those cylinders that are missing. Refer to Troubleshooting, "Injector Solenoid Circuit - Test".
Check for a problem with the fuel supply and verify the fuel pressure. For further information, refer to Testing and Adjusting, "Fuel System".
- Monitor the status of "Fuel Position" and "Rated Fuel Limit" on the electronic service tool. If "Fuel Position" does not equal "Rated Fuel Limit", then check the boost pressure.
- Verify that there are no active diagnostic codes that are associated with the boost pressure sensor.
- Monitor the status of "Boost Pressure" for normal operation on the electronic service tool.
Check air inlet and exhaust systems for restrictions and leaks. Refer to Testing and Adjusting, "Air Inlet and Exhaust System". Look for an indication of the Warning Lamp or restriction indicators that are tripped if the filters are equipped with these devices. These indicators are associated with plugged filters. Replace the plugged air filters or clean the plugged air filters per the guidelines for operation and maintenance., Repair any leaks that are found in the system.