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

Illustration 1	g00481278
Schematic For Alarm Module (ALM)

The alarm module (ALM) is available as an option. The ALM can be mounted on the instrument panel. The ALM can also be mounted at a distance as a remote annunciator. The ALM is used to satisfy requirements from customers and The National Fire Protection Association (NFPA) by annunciating the presence of a fault.

The ALM communicates with the GSC by a serial data link. When the data link malfunctions, all of the indicators on the ALM that are controlled by the data link, flash at a rate of .5 Hz.

Note: The maximum number of modules that can be connected to the serial data link is three. The maximum distance between a module and the GSC is 305 m (1000 ft). If these specifications are not met, there is a possibility for the ALM indicators to flash. Also, there is a possibility for the GSC to declare a diagnostic code of a CID 333. If the modules are not in compliance with the specifications, reduce the number of modules and/or shorten the distance to modules.

Note: Faults are created when the harness connector (40 contact) is disconnected from the GSC during these troubleshooting procedures. Clear these created faults after the particular fault is corrected. In a properly operating system, when the harness connector is removed from the GSC, the following diagnostic codes are recorded.

• CID 100 FMI 2 pressure sensor (engine oil)

• CID 110 FMI 2 temperature sensor (engine coolant)

• CID 111 FMI 3 fluid level sensor (engine coolant)

• CID 190 FMI 3 speed sensor (engine)

• CID 331 FMI 2 switch (engine control)

• CID 336 FMI 2 switch (engine control)

The following condition is a possible cause of a CID 333 FMI 4.

• A short to the "B-" of the signal for the data is present.

The GSC treats this diagnostic code as an alarm fault. Clear the diagnostic code from the fault log after troubleshooting is complete.

Note: If a CID 333 FMI 4 is showing on the upper display and no alarm module is installed, check for a short. Check between the auxiliary terminal strip and the GSC.

1. Check the fault status (Active/Inactive).

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

   2. Press the alarm codes key.

   3. Verify that a CID 333 FMI 4 is showing.

   4. If the diagnostic code is not showing, enter the service mode and view the fault log (OP1). Verify that the diagnostic codes are showing.

      Expected Result: A CID 333 FMI 4 is showing as active or inactive.

      Results:

      • No - A CID 333 FMI 4 has not occurred (is NOT active and is NOT inactive). STOP.

      • Yes - A CID 333 FMI 4 is active. Proceed to 2.

      • Yes - A CID 333 FMI 4 is inactive. Proceed to 4.

2. Check the voltage of the signal for the data.

   1. Turn the ECS to STOP.

   2. At the ALM, measure the DC voltage from terminal 2 (positive meter lead) to terminal 7 (negative meter lead).

      Expected Result: The voltage that is measured should change constantly. The voltage should change within the range of 0 to 10 DCV.

      Results:

      • OK - Voltage measurement is correct. Proceed to 4.

      • NOT OK - Voltage measurement is NOT correct. Proceed to 3.

3. Check the voltage of the ALM and the GSC.

   1. Turn the ECS to STOP.

   2. At the ALM, remove wire (18) from terminal 2.

   3. Disconnect the harness connector from the GSC.

   4. At the ALM, measure the DC voltage from terminal 2 (positive meter lead) to terminal 7 (negative meter lead). The voltage should be 11.6 ± 0.5 DCV.

   5. At the GSC, measure the DC voltage from contact 35 of the GSC, to the ground ("B-") terminal of the relay module. The measured voltage should change constantly. The voltage should change within the range of 0 to 5.5 DCV.

      Expected Result: For 3.d, the voltage should be 11.6 ± 0.5 DCV. For 3.e, the voltage should be changing constantly. The voltage should change within the range of 0 to 5.5 DCV.

      Results:

      • OK - Both voltage measurements are correct. Proceed to 4.

      • NOT OK - Voltage measured at the ALM is NOT correct. Replace the ALM. STOP.

      • NOT OK - Voltage measured at the GSC is NOT correct. Replace the GSC. STOP.

4. Check for a "B+" short in the harness.

   1. Disconnect the harness connector from the GSC.

   2. At the ALM, remove wire (18) from terminal 2.

   3. Measure the resistance from wire (18) at the ALM to the battery ("B+") at the relay module.

   4. Also, measure the resistance from wire (18) at the ALM to ground ("B-") at the relay module.

      Expected Result: For each measurement, the resistance should be greater than 20000 ohms.

      Results:

      • OK - Check the electrical connectors, terminals and wiring. See Testing And Adjusting, "Electrical Connector - Inspect". If the indicators on the ALM still flash after the inspection, replace the ALM. STOP.

      • NOT OK - One or both of the resistance measurements are less than 20000 ohms. The harness wiring with the incorrect resistance measurement is shorted. Troubleshoot and repair the faulty harness wiring between the ALM and the GSC. See the preceding System Schematic.