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

Illustration 1	g00616492
Schematic Of The Starting Motor Relay

The GSC uses the starting motor relay (SMR) to activate the following components: the starting motor magnetic switches ("SMMS1" and "SMMS2"), Start Aid Switch (3500 Only) and the optional prelube pump. The SMR is located within the relay module. "SMMS1" and "SMMS2" are located on the subpanel within the control panel.

Note: On the earlier 103-1582 EMCP II Control Panel (Chart), the SMR NC contacts were used to turn off the optional battery charger during activation of the starting motor magnetic switch.

Note: Whenever the GSC activates the SMR, "K4" is shown on the lower display. "K4" is also shown on the lower display when the GSC attempts to activate the crank terminate relay. When the SMR is not activated, "K4" is not shown.

Procedure

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

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

• If a CID 444 occurs, then the following events take place: the engine stops cranking, the prelube pump is disabled and the "AUTO" position of the starting aid switch is disabled. The battery charger will continue to function.

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

• If a CID 444 occurs, then the following events take place: the engine cannot crank, the engine cannot start, the prelube pump is disabled and the "AUTO" position of the starting aid switch is disabled. The battery charger will continue to function. If the engine is already running, then the engine continues to run.

The GSC treats a CID 444 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 shown 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 444 FMI 12 is showing.

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

      Expected Result: A CID 444 FMI 12 is showing as a active fault or an inactive fault.

      Results:

      • No - A CID 444 FMI 12 has not occurred (NOT active and NOT inactive). STOP.

      • Yes - A CID 444 FMI 12is 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 SMR.

   1. Turn the ECS to OFF/RESET.

   2. Disconnect all wires from RM-18 of the relay module.

   3. Remove the fuse "F4" from the relay module.

   4. At the relay module, measure the resistance from RM-18 to RM-6. Resistance should be greater than 5000 ohms.

   5. Prepare to measure the resistance from RM-18 to RM-6 of the relay module.

   6. Turn the ECS to the START position. Quickly measure the resistance before the starting motor relay deactivates because of the crank time. Resistance should be less than 5 ohms.

      Expected Result: For 3.d, the resistance should be greater than 5000 ohms. For 3.f, 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.