PLATE 0821235 - Caterpillar

MID 039 - Machine Control Module CID 3650 - Fire Suppression System Active Input FMI 03 - Voltage Above Normal
Illustration 1 g03206598This diagnostic code becomes active when the Input/Output Module (I/O Module) detects both inputs of the circuit to be OPEN. The fire suppression system is a customer supplied system. The system can only diagnose the switch to ground inputs that are connected to the I/O module.If a fire suppression system is not connected, use Cat ET to verify that the fire suppression system is set to "Not Installed". This setting can be found on the MCM "Configuration Tool" screen.The possible causes of this diagnostic code are listed below:
The return circuit is open.
Signal circuit 932-GN(Green) or corresponding switch contact wire is permanently open.
Signal circuit 931-GY(Grey) or corresponding switch contact wire is permanently open.
The switch has failed.
The Input/Output Module (I/O Module) has failed. This failure is unlikely.
Table 1
Status of the Switch/Circuit
MODE J2-31 (N/O)
931-GY(Grey) Circuit J2-36 (N/C)
932-GN(Green) Circuit
Inactive Open Closed
Active Closed Open Test Step 1. CHECK THE GROUND CIRCUIT FOR AN OPEN
Turn the disconnect switch and the keyswitch to the OFF position.
Disconnect the machine harness connectors from the I/O Module.
Disconnect the switch from the machine harness.
Measure the resistance between chassis ground and the ground contact at the connector for the switch. Expected Result:The resistance should be less than 5 ohms.Results:
OK - The resistance is less than 5 ohms. Proceed to Test Step 2.
NOT OK - The resistance is greater than 5 ohms.Repair: The return circuit is open in the machine harness. Repair the machine harness or replace the machine harness.STOPTest Step 2. CHECK THE SWITCH
Using Table 1 as a reference, verify proper operation of the switch on the fire suppression system. Note: Fire suppression system is customer supplied and the system can only detect issues that are connected to the two inputs of the I/O module.Expected Result:The continuity check agrees with the preceding Table.Results:
OK - The continuity check agrees with the preceding Table. Proceed to Test Step 3.
NOT OK - The