SWITCH AS 6T7663 - Caterpillar

Conditions Which Generate This Code:
Illustration 1 g01250926
Schematic of the Starter Motor RelayThis diagnostic trouble code is associated with the starter motor relay. The FMI 03 means that the ECU has determined that the voltage of the relay circuit is above normalThe possible causes of the diagnostic trouble code are listed:
The relay has failed.
The energize circuit of the relay is shorted to the +battery circuit.
The ECU has failed. This is unlikely.Note: The following test procedure may create other diagnostic trouble codes. Ignore these created diagnostic trouble codes and clear these diagnostic trouble codes when the original diagnostic trouble code has been corrected. Ensure that the diagnostic trouble code of CID 0444 FMI 03 is active before performing this procedure.Note: Use a digital multimeter for the measurements in this procedure.Test Step 1. CHECK THE ENERGIZE CIRCUIT OF THE RELAY FOR A SHORT TO THE +BATTERY CIRCUIT.
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness connectors from the relay and the ECU.
At the machine harness connector for the ECU, measure the resistance from contact J2-5 (wire 307-GN) to all contacts that are used in the machine harness connectors for the ECU. Expected Result:Each resistance measurement is greater than 5000 ohms. Results:
OK - Each resistance measurement is greater than 5000 ohms. The machine harness is correct. Proceed to Test Step 2.
NOT OK - Each resistance measurement is not greater than 5000 ohms. There is a short in the machine harness. The short is between J2-7 (307-GN) and the circuit that has a low resistance measurement. Repair: Repair the machine harness or replace the machine harness.STOPTest Step 2. CHECK IF THE DIAGNOSTIC TROUBLE CODE IS STILL ACTIVE.
Inspect the harness connectors and clean the contacts of the harness connectors and check the wires for damage to the insulation that is caused by excessive heat, battery acid, or chafing.
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit.
Reconnect all harness connectors making sure that the connectors are fully seated and the clips for each connector are completely fastened.
Turn the disconnect switch and the key start switch to the ON position.
Operate the machine.
Determine if the CID 0444 FMI 03 is active.Expected Result:The CID 0444 FMI 03 is active.Results:
YES - The CID 0444 FMI 03 is active. The problem has not been corrected.Repair: Check the circuit again. Use the Caterpillar Electronic Technician (ET) service tool, if available, in order to perform a "Wiggle Test" on the machine wiring harness. The wiggle test can detect momentary or intermittent shorts or opens in the machine wiring harness. It is unlikely that the ECU has failed. Exit this procedure and perform this procedure again. If the cause of the diagnostic trouble code is not found, replace the ECU. Prior to replacing an ECU, always contact your dealership's Technical Communicator for possible consultation with Caterpillar. This consultation may greatly reduce repair time. See Testing and Adjusting, "Electronic Control Unit - Replace".STOP
NO - The CID 0444 FMI