C-9 Engine for the 12H Motor Grader Caterpillar

Probable Causes

• Event codes

• Starting aids

• Throttle signal

• Turbocharger outlet pressure sensor

• Atmospheric pressure sensor

• Fuel supply

• Air inlet and exhaust system

• Accessory equipment

Recommended Actions

Event Codes

Connect the Caterpillar Electronic Technician (Cat ET) and check for an engine derate. Troubleshoot any event codes that are present before continuing with this procedure.

Starting Aids

Air Inlet Heater (If Equipped)

Make sure that the air inlet heater is programmed to On. For additional information on the air inlet heater, refer to Troubleshooting, "Air Inlet Heater Circuit - Test".

Oil Grade Plugs

Make sure that the "Oil Grade" is programmed correctly. For additional information, refer to the Operation and Maintenance Manual, "Engine Oil and Filter - Change".

Throttle Signal

Monitor "Throttle Position" on ET. Verify that you can achieve full throttle. Refer to Troubleshooting, "Throttle Position Sensor Circuit - Test" for the proper troubleshooting procedure.

Turbocharger Outlet Pressure Sensor or Atmospheric Pressure Sensor

1. Monitor the status of "Fuel Position", "Rated Fuel Limit", and "FRC Fuel Limit" on ET while the engine is operating under full load. These parameters should reflect the information below.
   Show/hide table

   Table 1

   "Fuel Position" = "Rated Fuel Limit"

   AND

   "Fuel Position" < "FRC Fuel Limit"

   If "Fuel Position" equals "Rated Fuel Limit" and "Fuel Position" is less than "FRC Fuel Limit", the electronics are operating correctly. Otherwise, proceed with the next Step.

2. Monitor the status of "Boost Pressure" and "Atmospheric Pressure" for normal operation on ET. When the engine is not running, "Boost Pressure" should be 0 kPa (0 psi).

3. Verify that the turbocharger outlet pressure sensor is operating properly.

Fuel Supply

1. Check the fuel lines for the following problems: restrictions, collapsed lines and pinched lines. If problems are found with the fuel lines, repair the lines and/or replace the lines.

2. Check the fuel tank for foreign objects which may block the fuel supply.

3. Check for air in the low pressure fuel supply system if any of the following procedures have been performed:
   • Replacement of the fuel filters

   • Service on the low pressure fuel supply circuit

   • Replacement of unit injectors

4. Purge air from the low pressure fuel supply circuit. Refer to Operation and Maintenance Manual, "Fuel System - Prime" for the correct procedure.

   Note: A sight glass in the low pressure supply line is helpful in diagnosing air in the fuel.

5. Check fuel quality. In temperatures below 0 °C (32 °F), check for solidified fuel (wax). Refer to Special Instruction, SEBD0717, "Diesel Fuels And Your Engine".

6. Check the fuel pressure during engine cranking. Check the fuel pressure on the outlet side of the fuel filter. Refer to Specifications for correct pressure values. If the fuel pressure is low, replace the fuel filters. If the fuel pressure is still low, check the following items: fuel transfer pump, fuel transfer pump coupling and fuel pressure regulating valve.

Air Inlet and Exhaust System

1. Clean plugged air filters or replace plugged air filters. Refer to the Operation and Maintenance Manual.

2. Check the air inlet and exhaust system for restrictions and/or leaks. Refer to Testing and Adjusting, "Air Inlet and Exhaust System".

Accessory Equipment

Check all accessory equipment for problems that may create excessive load on the engine. Repair any damaged components or replace any damaged components.