Electronic Modular Control Panel II (EMCP II) For MUI Engines Caterpillar

Illustration 1	g00616604
Schematic For Run Relay (RR)

The GSC uses the run relay (RR) in order to activate the electronic governor (EG). The GSC uses the RR to activate the starting aid switch ( 3500 Engines). The GSC provides a set of contacts of the run relay for the customer to use. The run relay is located within the relay module. The electronic governor (EG) is usually mounted on the subpanel within the control panel. The SAS is mounted on the instrument panel.

Note: A slave relay is used only for 3500 engines with the 2301A governor and without a fuel shutoff solenoid.

The GSC activates the run relay during engine cranking and running.

Note: Whenever the GSC activates the RR, "K5" is shown on the lower display. "K5" is also shown on the lower display when the GSC attempts to activate the crank terminate relay. When the RR is not activated, "K5" is not shown.

Procedure

The possible cause of this diagnostic code is an open coil or a shorted coil of the RR.

The following response is the system response to this fault while the RR is activated:

• If a CID 445 occurs, then the engine shuts down and the engine does not start. The "MAN" position of the starting aid switch (SAS) is disabled.

The following response is the system response to this fault while the RR is not activated:

• If a CID 445 occurs, then the engine cannot start. The "MAN" position of the starting aid switch (SAS) is disabled.

The GSC treats this diagnostic code as an alarm fault. Active alarm faults are shown on the display when the alarm codes key is pressed. Also, the active alarm faults are show when the ECS is in any position except the OFF/RESET position. Clear the diagnostic code from the fault log after troubleshooting is complete.

1. Check the status of the diagnostic code (Active/Inactive).

   1. Turn the ECS to OFF/RESET and then turn the ECS to STOP.

   2. Press the alarm codes key.

   3. Observe the upper display. Check that a CID 445 FMI 12 is showing.

   4. If this diagnostic code is not showing, enter the service mode. View the fault log (OP1). Check that the dagnostic code is showing.

      Expected Result: A CID 445 FMI 12 is showing as a active fault or an inactive fault.

      Results:

      • No - A CID 445 FMI 12 has not occurred (NOT active and NOT inactive). STOP.

      • Yes - A CID 445 FMI 12 is active or inactive. Proceed to 2.

2. Check internal cable of relay module.

   Note: Only open the relay module in a dry environment. If the inspection takes more than twenty minutes replace the desiccant bag in the GSC housing. See Testing And Adjusting, "Relay Module Replace".

   1. Turn the ECS to OFF/RESET.

   2. Temporarily, remove the relay module from the GSC. See Testing And Adjusting, "Relay Module - Replace".

   3. Check the cable that attaches the relay module to the GSC.

      Expected Result: The cable should be firmly seated in the connector. The clamp should be in place. The cable should not be damaged.

      Results:

      • OK - Reassemble the relay module to the GSC. Proceed to 3.

      • NOT OK - Replace the connector clamp if it is missing. If the cable is damaged, replace the GSC. STOP.

3. Perform a functional check for the RR.

   1. Turn the ECS to OFF/RESET.

   2. Disconnect all wires from RM-24 of the relay module.

   3. At the relay module, measure the resistance from RM-24 to RM-8. Resistance should be greater than 5000 ohms.

   4. Turn the ECS to the START position.

   5. At the relay module, measure the resistance from RM-24 to RM-8. Resistance should be less than 5 ohms.

      Expected Result: For 3.cthe resistance should be greater than 5000 ohms. For 3.e, the resistance should be less than 5 ohms.

      Results:

      • OK - It is likely that a temporary bad electrical connection existed and this troubleshooting procedure corrected it. Check the electrical connectors, terminals and wiring. See Testing And Adjusting, "Electrical Connector - Inspect". STOP.

      • NOT OK - Either one of the resistance measurements are NOT correct. The relay module is faulty. Replace the relay module. See Testing And Adjusting, "Relay Module - Replace". STOP.