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

Illustration 1	g00616656
Schematic For Air Shutoff Relay (ASR)

The GSC uses the air shutoff relay (ASR) to activate the air shutoff solenoid during a shutdown fault. The ASR is located within the relay module. The air shutoff solenoid are located within the air inlet system of the engine.

The GSC activates the air shutoff relay (ASR) for some active shutdown faults.

Note: Whenever the GSC activates the ASR, "K6" is shown on the lower display. "K6" is also shown on the lower display when the GSC attempts to activate the crank terminate relay. When the ASR is not activated, "K6" is not shown.

Procedure

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

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

• If a CID 446 occurs, then there is no effect on the system because the air shutoff is already operating and the shutdown mode is functioning.

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

• If a CID 446 occurs, then there is no immediate effect on the system. The engine is able to start and the engine is able to run.

The following response is the system response to this diagnostic code while the ASR is not activated and a shutdown fault occurs:

• If a CID 446 occurs, then the ASR cannot energize the air shutoff solenoids.

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 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 446 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 446 FMI 12 is showing as a active fault or an inactive fault.

      Results:

      • No - A CID 446 FMI 12 has not occurred (NOT active and NOT inactive). STOP.

      • Yes - A CID 446 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 ASR.

   1. Turn the ECS to OFF/RESET.

   2. Disconnect all wires from RM-19 of the relay module.

   3. At the relay module, measure the resistance from RM-19 to RM-5. Resistance should be greater than 5000 ohms.

   4. Turn the ECS to the STOP position and push in the emergency stop push button (ESPB).

   5. At the relay module, measure the resistance from RM-19 to RM-5. Resistance should be less than 5 ohms.

      Expected Result: For 3.c, the 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.