PLATE 8E9478 - Caterpillar

Table 3
Troubleshooting Test Steps Values Results
1. Identify Active FMI Code Associated With The Switch Circuit Code present FMI 2 diagnostic code, proceed to Test Step 2.
FMI 3 diagnostic code, proceed to Test Step 5.
FMI 4 diagnostic code, proceed to Test Step 8.
Begin Process For FMI 2 Troubleshooting HERE
2. Check The Switch
A. Turn the disconnect switch and the key start switch OFF.
B. Disconnect the switch from the machine harness.
C. Measure the resistance between the return or ground pin and all input pins, one at a time.
D. Move the switch through the range of selections, and verify continuity.
The resistance should be less than 5 Ω when switch operation indicates continuity, and greater than 5K Ω when switch operation indicates no continuity. OK - The resistance is as expected.
Proceed to Test Step 3.
NOT OK - The resistance is not as expected.
Repair: Replace the switch. Verify that the new switch resolves the diagnostic code.
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 switch. A resistance measurement that is greater than 5K Ω would indicate an open in the circuit.
Proceed to Test Step 10.
3. Check The Circuit For An Open
A. Turn the disconnect switch and the key start switch OFF.
B. Disconnect the switch and ECM from the machine harness.
C. Use a jumper wire between each contact on the machine harness at the switch end, one at a time.
D. Measure the resistance at the corresponding ECM harness pins.
The resistance is less than 5 Ω. OK - The resistance is less than 5 Ω.
Proceed to Test Step 4.
NOT OK - The resistance is greater than 5K Ω.
Repair: The circuit wire is open in the machine harness. 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.
Proceed to Test Step 10.
4. Check The Harness
A. The disconnect switch and key start switch remain in the OFF position.
B. Inspect the harness.
C. Check the connectors for proper mating.
D. Check the exposed wires for nicks and abrasions.
E. Check for moisture, dirt, or corrosion at connector locations.
The harness appears to be correct. OK - The harness appears correct.
Proceed to Test Step 10.
NOT OK - The harness appears to be damaged.
Repair: Repair the machine harness ot replace the machine harness.
Proceed to Test Step 10.
Begin Process For FMI 3 Troubleshooting HERE
5. Check The Signal Circuits For An Open
A. Turn the disconnect switch and the key start switch to the OFF position.
B. Disconnect the J1 machine harness connector from the ECM.
C. At the J1 harness connector, measure the resistance from the Normally Open contact to the ground contact with the switch in the normally open position. The switch is pressed.
D. At the J1 harness connector, measure the resistance from the Normally Closed contact to the ground contact with the switch in