Engine Cranks but Does Not Start
- Diagnostic codes
- Electrical power supply to the Electronic Control Module (ECM)
- Electrical connectors
- Personality module or incorrect engine software
- Flash file
- Engine speed signal
- Air inlet and exhaust system
- Fuel supply
- Engine shutdown switches (if applicable)
- Rack controls
- Combustion
Show/hide table
| Troubleshooting Test Steps | Value | Results |
|---|---|---|
1. Check for Diagnostic Codes, and Electrical Power Supply to the ECM. A. Certain diagnostic codes may prevent the engine from starting. Connect Cat® Electronic Technician (ET) and check for active codes and/or for logged codes. |
Diagnostic codes Supply voltage |
Result : The diagnostic codes and supply voltage are OK. Proceed to Test Step 2. Result : Result : The diagnostic codes and supply voltage are NOT OK. Repair : Troubleshoot any codes that are present before continuing with this procedure. If Cat ET will not communicate with the ECM, the problem is most likely with the electrical power supply to the ECM. Refer to Troubleshooting, "Electrical Power Supply - Test". If the problem is not resolved, proceed to Test Step 2. |
2. Check the Electrical Connectors. A. Disconnect the J1/P1 ECM connector. Inspect each connector for moisture and corrosion. Also, inspect the harness from the ECM to the sensors. |
Electrical connectors |
Result : The electrical connectors are OK. Proceed to Test Step 3. Result : The electrical connectors are NOT OK. Repair : Refer to Troubleshooting, "Electrical Connectors - Inspect". If the problem is not resolved, proceed to Test Step 3. |
3. Check the Personality Module or Incorrect Engine Software. A. Check for an active 252-11 diagnostic code. Also, check for an active 252-12 diagnostic code. |
ECM |
Result : The ECM is OK. Proceed to Test Step 4. Result : The ECM is NOT OK. Repair : Refer to Troubleshooting, "ECM/Personality Module - Test" if the code is present. If the problem is not resolved, proceed to Test Step 4. |
4. Verify the Flash File. |
Flash file |
Result : The flash file is OK. Proceed to Test Step 5. Result : The flash file is NOT OK. Repair : Download and install the latest flash file available. If the problem is not resolved, proceed to Test Step 5. |
5. Check the Engine Speed Signal. A. Crank the engine and observe the engine speed on the Cat ET status screen. B. Ensure that the timing reference gear is installed correctly. The engine will not start if the gear was installed backward. Check for proper orientation between the crankshaft and camshaft drive gears. |
Engine speed signal |
Result : The engine speed signal is OK. Proceed to Test Step 6. Result : The engine speed signal is NOT OK. Repair : If Cat ET indicates zero rpm, refer to Troubleshooting, "Engine Speed - Test". Correct the orientation and/or replace the drive gear, if necessary. Refer to the Disassembly and Assembly manual. If the problem is not resolved, proceed to Test Step 6. |
6. Check the Air Inlet and Exhaust System for Leaks and/or Restrictions. A. Check the air filter restriction indicator for a plugged filter. B. Check the air inlet and exhaust system for restrictions and/or leaks. |
Air inlet and Exhaust system |
Result : The air inlet and exhaust system are OK. Proceed to Test Step 7. Result : The air inlet system is NOT OK. Repair : If necessary, service the engine. Refer to the Operation and Maintenance Manual. Result : The exhaust system is NOT OK. Repair : Refer to Systems Operation/Testing and Adjusting. If the problem is not resolved, proceed to Test Step 7. |
7. Check the Fuel Supply. A. Visually check the fuel level. Do not rely on the fuel gauge only. B. Check the fuel lines for the following problems : restrictions, collapsed lines, and pinched lines. C. Check the fuel tank for foreign objects which may block the fuel supply. D. Prime the 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 Note : 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. |
Fuel supply |
Result : The fuel supply is OK. Proceed to Test Step 8. Result : The fuel supply is NOT OK. Repair : If necessary, add fuel. If the engine has been run out of fuel, it will be necessary to prime the fuel system. Refer to Operation and Maintenance Manual for the correct procedure. If problems are found with the fuel lines, repair the lines and/or replace the lines. Remove any foreign debris found in the fuel tank. If the problem is not resolved, proceed to Test Step 8. |
8. Check that the Engine Shutdown Switches (if applicable) Are Off. A. Use Cat ET to verify the status of the shutdown switches. When a shutdown occurs, the keyswitch must be turned to the OFF position for at least 15 seconds before restarting the engine. |
Engine shutdown switches |
Result : The engine shutoff switches are OK. Proceed to Test Step 9. Result : The engine shutoff switches are NOT OK. Repair : Turn off the engine shutdown switches and verify using Cat ET. If the problem is not resolved, proceed to Test Step 9. |
9. Check for Proper Operation of the Rack Controls. |
Rack controls |
Result : The rack controls are OK. Proceed to Test Step 10. Result : The rack controls are NOT OK. Repair : Refer to Troubleshooting, "Fuel Rack Solenoid - Test" and Troubleshooting, "Sensor Signal (Analog, Active) - Test". If the problem is not resolved, proceed to Test Step 10. |
10. Check the Combustion System. |
Combustion system |
Result : The combustion system is NOT OK. Repair : Troubleshoot and repair any problems found in the combustion system. |
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