- Customer specified parameters
- Cold mode
- Torque limit switch
- Electronic system
- Vehicle speed signal
- Power train data link
- Fuel supply
- Air Inlet and exhaust system
- Malfunction of an individual cylinder
- Low injection actuation pressure
- Derate from the monitoring system for the diesel particulate filter (if equipped)
- Establish communication between the Caterpillar Electronic Technician (Cat ET) and the engine Electronic Control Module (ECM).
- Check the "Engine Monitoring Mode" parameter.
- Check the value of the "Engine Monitoring Mode" parameter. If the parameter is programmed to "Derate", the ECM will derate the engine when certain problems occur. The derate is normal operation. Refer to Troubleshooting, "Caterpillar Engine Monitoring" for additional information.
- Check the following parameters:
- "Rating Number"
- "Top Engine Limit"
- "Vehicle Speed Limit"
- "Lower Gears Engine RPM Limit"
- "Intermediate Gears Engine RPM Limit"
- "Gear Down Protection Engine RPM Limit"
- "Rating Number"
- Set each parameter to the maximum value one at a time and determine whether the problem is corrected.
Note: Cold mode is normal operation if the problem occurs only after start-up in cold weather.
Monitor the status screen on Cat ET in order to verify that the engine has exited cold mode. An active cold mode is indicated in the upper corner of any status screen.
Check the setting for the "Torque Limit" parameter.
If the "Torque Limit" is programmed below 2712 N·m (2000 lb ft), check the status screen for the torque limit switch. Ensure that the status screen indicates that the torque limit switch is OFF. If the status of the torque limit switch is ON and a "Torque Limit" is programmed, the system is operating correctly. If the switch that is connected to this signal input is not switching on and switching off, refer to Troubleshooting, "PTO Switch Circuit - Test".
- Monitor the Fuel Position, the Rated Fuel Limit and the Fuel Limit for the Fuel Ratio Control (FRC).
While the vehicle is operating under full load, the parameters should meet the following conditions:
- The fuel position is equal to the rated fuel limit.
- The fuel position is less than the FRC limit.
If the fuel position is equal to the rated fuel limit and the fuel position is less than the FRC limit, the electronics are operating correctly. Proceed to "Vehicle Speed Signal".
- The fuel position is equal to the rated 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 limit, perform the following procedure:
- When the engine is off, turn the keyswitch to the ON position.
- Check the boost pressure on the status screen. The correct boost pressure is 0 kPa (0 psi).
Monitor the status of the accelerator pedal position sensor. Operate the engine at high idle with the vehicle in neutral.
If the engine cannot reach the programmed top engine limit, check the duty cycle of the accelerator pedal position sensor. Ensure that the duty cycle of the accelerator pedal position sensor is within calibration (75 to 90 percent at high idle).
If the accelerator pedal position is unstable, check the duty cycle of the accelerator pedal position sensor. Slowly operate 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 Troubleshooting, "Accelerator Pedal (Throttle) Position Sensor Circuit - 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 power is limited. If a problem is discovered, refer to Troubleshooting, "Vehicle Speed Circuit - Test".
- Check the power train data link. Ensure that the power train data link is not limiting the power.
- 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 the limit is not normal operation. If the limit is not normal operation, refer to the vehicle OEM for repairs.
- Check the fuel quality.
- Check the fuel pressure. Refer to Testing and Adjusting, "Fuel System Pressure - Test".
- Ensure that the fuel system has been primed. Refer to Testing and Adjusting, "Fuel System - Prime".
- 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 Testing and Adjusting, "Air in Fuel - Test".
- Check for leakage in the air-to-air aftercooler core . Refer to Testing and Adjusting, "Aftercooler - Test".
- Check the air inlet system for restrictions and for leakage. Check the exhaust system for restrictions and for leakage. Refer to Testing and Adjusting, "Air Inlet and Exhaust System - Inspect".
- Ensure that the J300/P300 electronic unit injector connector is free of corrosion and that the connector is fully connected.
- Ensure that the J2/P2 ECM connector is fully connected and ensure that the ECM connector is free of corrosion.
- Perform the "Cylinder Cutout Test". Access the "Cylinder Cutout Test" by selecting the "Diagnostic Menu" and the "Diagnostics Test 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".
- Perform a Performance Analysis Report (PAR).
Low Injection Actuation Pressure
- Check the engine oil level. Engine oil is used to activate the high pressure hydraulic pump.
- Ensure that the engine oil meets the recommendations of the engine manufacturer. Refer to the Operation and Maintenance Manual for further details.
- Refer to Troubleshooting, "Injection Actuation Pressure -Test".
Check the Monitor for the Diesel Particulate Filter (If Equipped)
The monitor for the diesel particulate filter can be configured to derate the engine if the differential pressure across the filter becomes excessive.
Determine if the monitor is configured to derate the engine. If the monitor is configured to derate the engine, check the monitor. Determine if there is a warning for high pressure. If there is a warning for high pressure, clean the filter according to the most recent guidelines.