- Electrical connections
- Engine monitoring
- Electronic system
- Accelerator pedal position sensor
- Vehicle speed signal
- Power train data link
- Fuel supply
- Torque limit switch
- Low injection actuation pressure
Check the Electrical Connectors
Verify that the following connectors are installed correctly:
- Electrical connectors for the ECM
- Connectors for the wiring harness under the valve cover
- Connectors for the engine speed/timing sensors
Use the Caterpillar Electronic Technician (ET) to verify that the "Engine Monitoring Mode" parameter is programmed to the desired option:
- Warning
- Derate
- Shutdown
Use Cat ET to monitor the fuel position, the rated fuel limit and the FRC fuel limit. While the vehicle is operating under full load, the parameters should meet the following conditions:
If the fuel position is equal to the rated fuel limit and the fuel position is less than the FRC fuel limit, the electronics are operating correctly. Proceed to "Check the Fuel Supply".
- The fuel position is equal to the rated fuel limit.
- The fuel position is less than the FRC fuel limit.
If the fuel position is not equal to the rated fuel limit and/or the fuel position is not less than the FRC fuel limit, Use Cat ET to check the intake manifold pressure when the engine is not running. The correct intake manifold pressure is
Accelerator Pedal Position Sensor
Monitor the status of the accelerator pedal position sensor. Operate the engine at high idle with the vehicle in neutral. Verify that the duty cycle is between 75 percent and 90 percent at high idle. The value should be stable.
If the accelerator pedal position is unstable, check the duty cycle of the accelerator pedal position sensor. Check the duty cycle of the accelerator pedal position sensor by slowly operating the accelerator pedal in order to verify that the accelerator pedal position sensor is within calibration. The accelerator pedal position sensor is within calibration when both of the following conditions are met:
- 10 to 22 percent at low idle
- 75 to 90 percent at high idle
Also, ensure that the duty cycle changes as the pedal position changes.
If a problem with the accelerator pedal position sensor is suspected, refer to the circuit test Troubleshooting, "Sensor Signal (PWM) - Test".
Monitor the vehicle speed signal. Ensure the accuracy of the vehicle speed signal by comparing the vehicle speed signal to the actual vehicle speed.
If the vehicle speed is greater than the "VSL", the ECM will limit the engine's power. Refer to the circuit test Troubleshooting, "Vehicle Speed - Test".
Check the "Powertrain Data Link". Ensure that the power train data link is not limiting the engine's power.
Use Cat ET to monitor the "Powertrain Data Link" status screen while the vehicle is experiencing problems. If the "Powertrain Data Link" status screen indicates that the data link is limiting the power or the rpm, verify that this is not normal operation. If this is not normal operation, refer to the vehicle OEM for repairs.
Check the fuel quality. For further information, refer to Operation and Maintenance Manual, SEBU6385, "Caterpillar On-Highway Diesel Truck Engine Fluid Recommendations".
Check the fuel pressure. Refer to Systems Operation/Testing and Adjusting, "Fuel System".
Ensure that the fuel system has been primed. Refer to Systems Operation/Testing and Adjusting, "Fuel System".
Check for fuel supply lines that are restricted.
Check the fuel filters.
Cold weather adversely affects the characteristics of the fuel. Refer to the Operation and Maintenance Manual for information on improving the characteristics of the fuel during cold weather operation.
Check for air in the fuel system. Refer to Systems Operation/Testing and Adjusting, "Fuel System".
Check the setting for the customer parameter for the "Torque Limit".
If the "Torque Limit" is programmed below