GLASS 1535906 - Caterpillar

Table 1
Troubleshooting Test Steps Values Results
1. CHECK THE KEY.
A. Connect the Cat Electronic Technician (Cat ET) to the Service Connector.
B. Insert a valid electronic key for the machine in the key start switch.
C. Turn the key switch to the ON position.
D. Go to the "Service/Security Management" screen. Check the "Current Key Information".
E. Check the "ID1" and "ID2" for the key that is in the key start switch.
The MSS reads the ID1 code and the ID2 code as 0. Yes - The MSS reads the ID1 code and the ID2 code as 0. The key may have failed or the problem may exist in the exciter coil.
Proceed to Test Step 2.
No - The MSS reads the ID1 code and the ID2 code correctly. The key has been read by the MSS3s ECM, but the MSS is still armed. The MSS still armed, indicates that the key in the key start switch is not authorized for that machine.
Repair: Program that key into the MSS3s ECM or use a different key.
STOP.
2. CHECK THE EXCITER COIL.
A. Disconnect the exciter coil from the wiring harness.
B. Measure the resistance on the leads of the exciter coil.
The resistance is approximately 1 ohm. Yes - The resistance is approximately 1 ohm.
Proceed to Test Step 3.
No - The resistance is greater than approximately 1 ohm. The exciter coil has failed.
Repair: Replace the exciter coil.
STOP.
3. CHECK THE WIRING OF THE MACHINE HARNESS FOR AN OPEN CIRCUIT.
A. The exciter coil remains disconnected from the wiring harness.
B. On the harness side of the connector for the exciter coil, install a jumper wire between pin 1 and pin 2 .
C. Disconnect the wiring harness connector from the MSS3s ECM.
D. Measure the resistance between pin 7 and pin 53 of the connector for the MSS3s ECM.
The resistance is less than 5 ohms. Yes - The resistance is less than 5 ohms between pin 7 and pin 53. The wiring for the exciter coil is correct
Proceed to Test Step 4.
No - The resistance is greater than 5 ohms between pin 11 and pin 13. There is a problem in the wiring for the exciter coil.
Repair: Check the wiring harness for signs of damage. Repair or replace the machine harness.
Note: The "ferrite coil" assembly is wired in series with the harness of the exciter coil. Locate the "ferrite coil" assembly. The "ferrite coil" assembly is located near the 70-pin connector of the MSS3s ECM. Continuity should exist through the coil assembly.
STOP.
4. CHECK THE WIRING OF THE MACHINE HARNESS FOR A SHORT TO GROUND.
Note: The output drivers of the MSS3s ECM are protected from excessive electrical current. Excessive electrical current is usually the result of a wire or a component that is shorted to ground. If the MSS3s ECM detects an excessive amount of electrical current, the MSS3s ECM will disable the output driver.
A. The wiring harness connector for the MSS3s ECM and the exciter coil remain disconnected.
B. The jumper wire remains installed.
C. Measure the resistance between pin 7 of the MSS3s ECM and frame