STUD 0000221 - Caterpillar

problem exists in the exciter coil, the MSS will be unable to read the electronic key. If the wiring for the exciter coil is damaged, the MSS will be unable to read the electronic key.Note: Ensure that you have only one electronic key near the exciter coil when the MSS reads the key. If there is more than one key the MSS ECM will not be able to read the key and the machine will not start.Test Step 1. CHECK THE KEY.
Connect the Caterpillar Electronic Technician (ET) to the Service Connector.
Insert a valid electronic key for the machine in the key start switch.
Turn the key switch to the ON position.
Go to the "Service/Security Management" screen. Check the "Current Key Information".
Check the "ID1" and "ID2" for the key that is in the key start switch.Expected Result:The MSS reads the ID1 code and the ID2 code as 0.Results:
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 MSS ECM, but the MSS is still armed. This indicates that the key in the key start switch is not authorized for that machine.Repair: Program that key into the MSS ECM, or use a different key.STOPTest Step 2. CHECK THE ET DIAGNOSTIC SCREEN.
Check the ET diagnostic screen for a communication error between the machine ECM and the Key Reader Module.Note: The key reader communication diagnostic code is CID 1960 FMI 09.Expected Result:The ET reports CID 1960 FMI 09 as active or the diagnostic code has been logged.Results:
YES - The ET reports CID 1960 FMI 09 as active or the diagnostic code has been logged.Repair: Troubleshoot the CAN data link connections between the key reader module and the machine ECM. Proceed to Test Step 8.
NO - The diagnostic code has NOT been logged or the diagnostic is NOT active. Proceed to Test Step 3.Test Step 3. CHECK FOR POWER TO THE KEY READER MODULE.
With the key switch in the ON position, check for system voltage between pin 1 and pin 2 of the key reader module.Expected Result:The voltage that is measured is approximately system voltage.Results:
YES - The voltage that is measured is approximately system voltage. The voltage is correct. Proceed to Test Step 4.
NO - System voltage is NOT present. The wiring harness has failed.Repair: Check the wiring harness for signs of damage. Repair the machine harness or replace the machine harness.STOPTest Step 4. CHECK THE EXCITER COIL.
Disconnect the exciter coil from the wiring harness.
Measure the resistance on the leads of the exciter coil. Expected Result:The resistance is approximately 1 ohm.Results:
YES - The resistance is approximately 1 ohm. Proceed to Test Step 5.
NO - The resistance is greater than approximately 1 ohm. The exciter coil has failed.Repair: Replace the exciter coil.STOPTest Step 5. CHECK THE EXCITER COIL WIRING OF THE MACHINE