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

Illustration 1	g00596452
Schematic For Electrical System

The EMCP II monitors battery voltage in order to protect the EMCP II in case of a problem with the battery or battery charging. The EMCP II operates on a 24 DCV battery system or a 32 DCV battery system. The GSC receives battery voltage from RM-1 of the relay module terminal strip. The GSC measures this voltage. Voltage is received whenever the ECS is in the "START", "AUTO", or "STOP" position.

Note: The GSC does not receive battery power when the ECS is in the OFF/RESET position. The GSC receives power when the contacts "6" and "9" of the ECS are jumpered.

The GSC treats a CID 168 as an alarm fault.

Procedure

This diagnostic code can be caused by the following conditions:

• The battery voltage is greater than 32 DCV for a 24 DCV battery system.

• The battery voltage is greater than 45 DCV for a 32 DCV battery system.

The setpoint for system voltage (P07) specifies the battery voltage as "0" for 24 volts and "1" for 32 volts. Clear the diagnostic code from the fault log after troubleshooting is complete.

This procedure is used for troubleshooting an active fault or an inactive fault. Active alarm faults are shown on the upper display when the alarm codes key is pressed and the ECS is in any position except the OFF/RESET position. Inactive alarm faults are viewed in the fault log while the operator is in service mode. See Systems Operation, "Fault Log Viewing OP1".

1. Verify the fault.

   1. View the upper display and check for active diagnostic faults for the battery voltage (CID 168 FMI 03).

   2. Enter service mode and check the fault log for inactive diagnostic codes for the battery voltage (CID 168 FMI 03).

      Expected Result: A CID 168 FMI 03 diagnostic code is active.

      Results:

      • YES - A CID 168 FMI 03 diagnostic code is active. Proceed to Step 2.

      • NO - There are no diagnostic codes for the battery voltage. STOP.

2. Check the system's voltage.

   1. Turn the ECS to the STOP position.

   2. Measure the voltage across the battery terminals.

      Expected Result: For a 24 volt system, the voltage should be between 24.8 DCV and 29.5 DCV. For 32 volt system, the voltage should be between 33.1 DCV and 39.3 DCV.

      Results:

      • OK - For a 24 volt system, the voltage should be from 24.8 DCV to 29.5 DCV. For a 32 volt system, the voltage should be from 33.1 DCV to 39.3 DCV. Proceed to Step 3.

      • NOT OK - For 24 volt systems, the voltage is not between 24.8 DCV to 29.5 DCV. For a 32 volt system, the voltage is not between 33.1 DCV to 39.3 DCV. The fault is in the charging system. Proceed to Testing and Adjusting, "Charging System - Test". STOP.

3. Compare the voltage between TS1-1 and the battery voltage.

   1. Turn the ECS to the STOP position.

   2. Measure the battery voltage across the terminals. Take note of the battery voltage.

   3. Measure the voltage between TS1-1 and TS1-30. Take note of the voltage.

   4. Compare the voltage from Step 3.b with the voltage that was noted in Step 3.c.

      Expected Result: The voltages that are measured in Step 3.b and Step 3.c are within 2.0 DCV of each other.

      Results:

      • OK - The voltages that are measured in Step 3.b and Step 3.c are within 2.0 DCV of each other. Proceed to Step 4.

      • NOT OK - The voltages that are measured in Step 3.b and Step 3.c are not within 2.0 DCV of each other. The wiring harness is not correct. Repair the wiring harness or replace the wiring harness. STOP.

4. Compare the voltage between the TS1-1 and the ECS.

   1. Turn the ECS to the STOP position.

   2. Measure the voltage between TS1-1 and TS1-30. Take note of the voltage.

   3. Measure the voltage at terminal 6 on the ECS. Take note of the voltage.

   4. Compare the measured voltage from Step 4.b with the voltage that was measured in Step 4.c.

      Expected Result: The voltages that are measured in Step 4.b and Step 4.c are within 2.0 DCV of each other.

      Results:

      • OK - The voltages that are measured in Step 4.b and Step 4.c are within 2.0 DCV of each other. Proceed to Step 5.

      • NOT OK - The voltages that are measured in Step 4.b and Step 4.c are not within 2.0 DCV of each other. The wiring harness is not correct. Repair the wiring harness or replace the wiring harness. STOP.

5. Check the continuity of the ECS.
   Show/hide table

   Table 1

   Engine Control Switch (ECS) (1) (2)
   Terminal	OFF/RESET	AUTO	MANUAL	STOP
   7	X	O	O	O
   8	O	X	O	O
   9	O	O	X	O
   10	O	O	O	X

   Show/hide table

   ( 1 )	X = Less than 5 Ohms resistance from this terminal to terminal 6 (ECS).
   ( 2 )	O = Greater than 5000 Ohms resistance from this terminal to terminal 6 (ECS).

   1. Disconnect the jumper from 6 to jumper 9 from the ECS.

   2. Place the ECS in the OFF/RESET.

   3. Place the one lead on terminal 6 of the ECS.

   4. Measure the resistance from terminal 6 to each of the terminals ( 7, 8, 9, and 10).

   5. Use the same procedure for each switch position.

   6. Compare the measured resistances with Table 1.

      Expected Result: The measured resistances match Table 1.

      Results:

      • OK - The measured resistances match Table 1. The ECS is not faulty. Proceed to Step 6.

      • NOT OK - The measured resistances match Table 1. The ECS is faulty. Replace the ECS. Reinstall the jumper wire.

6. Compare the voltage between RM-1 and the ECS.

   1. Turn the ECS to the STOP position.

   2. Check the voltage between RM- 1 and RM-28. Take note of the voltage.

   3. Check the voltage on contact 10 of the ECS. Take note of the voltage.

   4. Compare the voltage between Step 6.b and Step 6.c.

      Expected Result: The voltages that were measured in Step 6.b and Step 6.c are within 2.0 DCV of each other.

      Results:

      OK - The voltages that were measured in Step 6.b and Step 6.c are within 2.0 DCV of each other. The harness is correct. Proceed to Step 7.

      NOT OK - The voltages that were measured in Step 6.b and Step 6.c are not equal ± 2.0 DCV. The wiring harness is faulty. Repair the harness or replace the harness. STOP.

7. Compare the voltage between RM-1 and the lower display.

   1. Turn the ECS to the STOP position.

   2. Check the voltage between RM- 1 and RM-28. Take note of the voltage.

   3. Check the voltage that is shown on the lower display. Take note of the voltage.

   4. Compare the voltage between Step 7.b and Step 7.c.

      Expected Result: The voltages that were measured in Step 7.b and Step 7.c are within 2.0 DCV of each other.

      Results:

      OK - The voltages that were measured in Step 7.b and Step 7.c are within 2.0 DCV of each other. The fault is probably an intermittent fault which is caused by a faulty connector. Inspect the electrical connectors. See Testing and Adjusting, "Electrical Connector - Inspect". If the faulty connector can not be found, repeat this test procedure. If the fault still remains, replace the GSC. STOP.

      NOT OK - The voltages that were measured in Step 7.b and Step 7.c are not equal ± 2.0 DCV. The GSC is faulty. Replace the GSC. STOP.