PLATE ASSEM. 2N4518 - Caterpillar

Diagnostic Trouble Code (DTC) Root Causes and Schematics
Possible Causes for an FMI 3 Diagnostic code are:
The relay has failed.
The energize circuit of the relay is shorted to the +battery circuit.
The indicator lamp has failed.
The ECM has failed. ECM failure is unlikely.Possible Causes for an FMI 5 Diagnostic code are:
The relay has failed.
There is an open in the circuit.
The ECM has failed. ECM failure is unlikely.Possible Causes for an FMI 6 Diagnostic code are:
The energizer circuit of the relay is shorted to ground.
The relay has failed.
The ECM has failed. ECM failure is unlikely.
Illustration 1 g03353418
Illustration of the relay connections for the Transmission ECM J1 circuit
Illustration 2 g03358944
Illustration of the relay connections for the Transmission ECM J2 circuit
Note: The diagrams above are simplified schematics of the relays and the relay connections for the Transmission ECM. The schematic is electrically correct. However, not all of the possible harness connectors are shown. Refer to the latest revision of Electrical Schematic, RENR9783 for the complete schematic.Troubleshooting Procedure
Note: Prior to beginning this procedure, inspect the harness connectors that are involved in the circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, secure and in good condition. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure.
Table 2
Troubleshooting Test Steps Values Results
1. Identify Active FMI Code Associated With Relay Circuit
Code present. FMI 3 diagnostic code, proceed to Test Step 2.
FMI 5 diagnostic code, proceed to Test Step 3.
FMI 6 diagnostic code, proceed to Test Step 5.
Begin Process For FMI 3 Troubleshooting HERE
2. Check The Machine Harness For A Short
A. Turn key start switch and disconnect switch OFF.
B. Disconnect harness connection at relay.
C. If relay connected to ECM, disconnect J1 and J2 connectors from ECM. If relay connected to Switch Panel, disconnect all Switch Panel connectors.
D. Measure resistance of relay signal contact to all J1 and J2 connectors, if relay is wired directly to Transmission ECM. If relay is wired directly to switch panel, measure resistance of relay contact to all switch panel connectors.
Each reading is greater than 5K Ω. OK: All resistance measurements are greater than 5K Ω.
Proceed to Test Step 7.
NOT OK: One or more readings are less than 5 Ω.
Repair: A short exists between the signal contact and the circuit with the low resistance. Repair or replace the machine harness.
Note: A resistance that is greater than 5 Ω but less than 5K Ω would indicate a loose connection or a corroded connection in the circuit. A resistance measurement that is greater than 5K Ω would indicate an open in the circuit.
STOP
Begin Process For FMI 5 Troubleshooting HERE
3. Check The Relay
A. Turn the key start switch and the disconnect switch OFF.
B. Remove the relay.
C. Place a jumper wire between the signal contact and the return contact of the relay.
D. Turn the key start switch and the disconnect switch ON. Do not start the engine.
E. As the jumper is