STUD 1161316 - Caterpillar

Illustration 1 g02474097
This diagnostic code is associated with the Joystick Steering Enable Switch. The switch supplies two switch-to-ground type inputs to the Machine ECM. The ECM expects one of the two switch inputs to be grounded at all times.When the ECM detects that neither of the switch inputs is grounded, the ECM will activate an FMI 03 diagnostic code for voltage above normal.Possible conditions that can cause this diagnostic code are listed:
A switch circuit is open in the machine harness.
A switch circuit is shorted to a voltage source.
The switch has failed.
The Machine ECM has failed. This situation is unlikely.System Response:When the ECM activates this diagnostic code, the ECM disables the joystick steering system.Before performing 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. Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the original diagnostic code has been corrected.Note: The components connected to the Switch Panel are monitored by the Machine ECM via the CAN B data link.Test Step 1. CHECK THE SWITCH INPUT CIRCUITS FOR AN OPEN
Turn the disconnect switch and the key switch to the OFF position.
At the Joystick Steering Enable Switch, connect a jumper wire between the normally closed (N/C) contact 4 (wire J993-PK) and the normally open (N/O) contact 6 (wire J994-GY).
Disconnect the machine harness connector C15 from the Switch Panel.
At the Switch Panel connector C15, measure the resistance between N/C contact C15-15 (wire J993-PK) and N/O contact C15-14 (wire J994-GY).
While observing the multimeter resistance measurement, wiggle the machine harness connectors. Gently pull on the wires and move the wires around.Expected Result:The resistance measurement is less than 5 ohms at all times during the manipulation of the harness and connectors.Results:
OK - The resistance measurement is less than 5 ohms. The switch input circuits are not open in the machine harness. Proceed to Test Step 2.
NOT OK - The resistance measurement is greater than 5 ohms. One of the switch circuits is open or has a poor connection in the machine harness. Repair: There is an open or a poor connection in switch input wire J993-PK or switch input wire J994-GY. Check each circuit individually in order to determine which circuit has the problem. Refer to the complete machine Electrical System Schematic. Verify that all connection points for the circuit are clean, secure and in good condition. Repair the machine harness or replace the machine harness. STOPTest Step 2. CHECK THE SWITCH GROUND CIRCUIT FOR AN OPENThe disconnect switch and the key switch remain in the OFF position. The machine harness connector C15 remains disconnected from the Switch Panel.
At the Joystick Steering Enable Switch, connect the jumper wire that was