3126B Petroleum Engine Caterpillar

Show/hide table

The connection of any electrical equipment and the disconnection of any electrical equipment may cause an explosion hazard which may result in injury or death. Do not connect any electrical equipment or disconnect any electrical equipment in an explosive atmosphere.

Note: Use this procedure only if the engine shut down completely and it was necessary to restart the engine.

Probable Causes

• Diagnostic codes or event codes

• Engine parameters

• Electrical connections

• Electronic unit injector connector

• Fuel supply

• Injection actuation pressure control system

• Remote shutdown switch (if equipped)

Note: If the problem only occurs under certain conditions such as high engine speed, full load or engine operating temperature, then perform the test under those operating conditions.

Recommended Actions

Diagnostic Codes or Event Codes

Certain diagnostic codes and/or event codes may cause the engine to shutdown. Connect the Caterpillar Electronic Technician (ET) and check for active codes and/or for logged codes. Troubleshoot any codes that are present before continuing with this procedure.

Engine Parameters

The engine may be shut down due to low pressure levels or other factors. Connect Cat ET and check for active shutdowns or diagnostic codes.

If a shutdown is active, "Injection Disabled" will appear in the third box of any status screen on Cat ET.

An engine shutdown event will appear on a CAN J1939 device if the device is capable of displaying diagnostic codes.

Electrical Connections to the ECM

1. thoroughly inspect the J1/P1 and the J2/P2 ECM connectors. Inspect the J401/P401 and the J402/P402 engine speed/timing sensor connectors. Refer to Troubleshooting, "Electrical Connectors - Inspect".

2. Check Cat ET for a 168-02 System Voltage intermittent/erratic that is active or logged.

   Check the battery connection at the J1/P1 ECM connector and the J61 customer connector. Refer to the Electrical System Schematic for your engine.

   Perform a pull test on the following power terminals:

   • P1-48 Unswitched +Battery

   • P1-52 Unswitched +Battery

   • P1-53 Unswitched +Battery

   • P1-61 -Battery

   • P1-63 -Battery

   • P1-65 -Battery

   • P1-70 Switched +Battery

   • P61-1 Unswitched +Battery

   • P61-26 Switched +Battery

   • P61-31 Unswitched +Battery

   • P61-32 Unswitched +Battery

   Refer to Troubleshooting, " Electrical Connectors - Inspect".

Note: The problem may only occur when the engine is at normal operating temperature. As the engine cools, the problem may disappear. The circuit breakers may be exceeding the trip point because of the overheating. Check the circuit breakers on the engine. If necessary, reset the circuit breakers.

Note: Aftermarket engine protection devices usually interrupt power to the ECM. Check for correct installation and for operation of aftermarket engine protection devices. It may be necessary to bypass aftermarket devices in order to continue testing.

Electronic Unit Injector Connector

Thoroughly inspect the J300/P300 unit injector connector. Refer to Troubleshooting, "Electrical Connectors - Inspect".

Check the Fuel Supply

1. Check the fuel level.

2. Monitor the exhaust for smoke while the engine is being cranked.

   If no smoke is present, there may be a problem with the fuel quality or there may be a problem with the fuel supply.

3. Check the fuel pressure. Refer to Systems Operation/Testing and Adjusting, "Fuel System Pressure - Test".

4. Ensure that the fuel system has been primed. Refer to Systems Operation/Testing and Adjusting, "Fuel System - Prime".

5. Check for fuel supply lines that are restricted.

6. Check the fuel filters.

7. Cold weather adversely affects the characteristics of the fuel. Refer to Special Publication, SEBU6251, "Commercial Diesel Engine Fluids Reccomendations" for information on improving the characteristics of the fuel during cold weather operation.

Injection Actuation Pressure Control System

1. Use Cat ET to check the injection actuation pressure.

   1. Crank the engine and monitor the injection actuation pressure.

   2. Monitor the output of the injection actuation pressure control valve.

      The high pressure oil system is operating properly if the pressure output is a minimum of 6 MPa (870 psi).

2. Check for a 164-11 injection actuation pressure system fault. If the diagnostic code has been logged recently, refer to Troubleshooting, "Injection Actuation Pressure Control Valve Circuit - Test".

3. If higher than actual pressure is being indicated, then disconnect the injection actuation pressure sensor and try to start the engine. If the engine starts, refer to Troubleshooting, "Injector Actuation Pressure Sensor -Test".

Remote Shutdown Switch (If Equipped)

Access the Cat ET screen that displays the remote shutdown switch status. The remote shutdown switch status on the Cat ET is called "User Shutdown".

If the voltage is not in the proper range, refer to the appropriate reference material for more information.