Troubleshooting Caterpillar Starter Failure

  (1) Possible Causes 

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1) Diagnostic Codes 

2) Event Codes 

 3) ECM Power Supply

 4) Oil Level 

5) Starter Assist Devices 

6) Engine Stop Switch 

7) Engine Speed/Timing 

8) Injection Drive Pressure

 9) Individual Injectors 

10) Fuel Supply

 11) Combustion Fault

 

 (2) Recommended Actions. 

 1) Diagnostic Codes, Event Codes, and ECM Power Supply. Some diagnostic codes and/or event codes can prevent the engine from starting. Connect the Caterpillar Electronics Technology (Cat ET) and check for any current and/or recorded codes. Before continuing this procedure, troubleshoot and resolve any existing codes. Note: If the Cat ET cannot communicate with the ECM, the problem is most likely with the power supply to the ECM; see the "Testing the Power Supply Circuit" section. 

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 2) Oil Level. Check the engine oil level. Add oil if necessary. Note: Engine oil supplies the fuel injection drive pressure circuit. Maintaining the correct engine oil level is necessary for fuel injection.

  3) Starting Assist Devices.

 ① Intake Air Heater. Verify that the intake air heater is set to the ON position. 

 ② Engine Stop Switch (if equipped). The engine stop switch should be in the OFF position. Use the Cat ET to check the status of the stop switch. When parking, the key switch should be turned to the OFF position for at least 15 seconds before restarting the engine.

 

 Note: If the Cat ET cannot communicate with the ECM, the problem is most likely with the power supply to the ECM. Please refer to the "Testing the Power Supply Circuit" section.

 4) Engine Speed/Timing.

 ① Rotate the engine and observe the engine speed on the Cat ET status screen. If the Cat ET displays Or/min, please refer to the "Testing the Engine Speed/Timing Sensor Circuit" section. Note: On the first rotation, the engine status may show an abnormal engine speed signal. Once the ECM can calculate the engine speed from the signal, this information will be replaced by the engine speed. 

 ② Verify that the timing reference gear is installed correctly. If the gear is installed backwards, the engine will not start. Check the alignment between the crankshaft and camshaft drive gears. If necessary, correct the alignment and/or replace the drive gears.

 

 5) Injection Drive Pressure. 

 ① Rotate the engine and monitor the injection drive pressure and the output pressure of the injection drive pressure control valve. If the pressure output is not lower than 6MPa, the high-pressure fuel system is considered to be operating normally. 

 ② If the displayed pressure is higher than the current pressure, disconnect the fuel injection drive pressure sensor and try starting the engine. If the engine starts, refer to the "Testing the Fuel Injection Drive Pressure Sensor" section.

 6) Individual Injectors. Perform an "Injector Solenoid Coil Test" on a Cat ET to determine if all injector solenoid coils are energized by the ECM.

 

 

7) Fuel Supply. 

 ① Visually check the fuel level. Do not rely solely on the fuel gauge. Add fuel if necessary. If the engine runs out of fuel, air must be purged from the fuel system. 

② Check the fuel lines for the following problems: throttling, collapsed, and clamped lines. If any fuel lines are faulty, repair and/or replace them. 

③ Check the fuel tank for foreign objects, which can block the fuel supply. 

 ④ If any of the following procedures have been performed: replacing the fuel filter, repairing the low-pressure fuel supply circuit, or replacing the individual injectors, check for air in the low-pressure fuel supply system. Note: The sight glass in the low-pressure fuel supply line helps diagnose air in the fuel. Note: Do not crank the engine continuously for more than 30 seconds. Allow the starter motor to cool down for 2 minutes before cranking the engine again. 

 

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 ⑤ Bleed the air from the low-pressure fuel supply circuit. 

 

 ⑥ Check the fuel quality. If the temperature is below 0°C, check for solidified fuel (waxy substances). 

 

 ⑦ While cranking the engine, check the fuel pressure after the fuel filter. If the fuel pressure is low, replace the fuel filter. If the fuel pressure is still low, check the following: fuel pump, fuel pump coupling, and fuel pressure regulating valve. 

 

 8) Combustion problems. Check for combustion problems.