ENGINE AR 2515863 - Caterpillar

Illustration 1 g01227576
Mode select switch connectionsThe mode select switch is the left push-button switch on the electronic hydraulic blade control handle. The switch provides a Normally Closed input of the ECM and the switch has a Normally Open input to the ECM. This switch is used to indicate to the ECM that the Accugrade system should go to AUTO mode. This diagnostic code is recorded when the ECM detects that the voltage of one or both of the switch input circuits is above normal.The possible causes of this diagnostic code are listed:
The switch is faulty.
The Normally Open circuit of the switch is shorted to the +battery circuit.
The Normally Closed circuit of the switch is shorted to the +battery circuit.
The ECM has failed. This is unlikely.Note: Ensure that CID 0874 FMI 03 is on hold and that the fault present indicator shows "SERV CODE".Test Step 1. CHECK THE SWITCH
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness from the 12 contact blade control handle connector.
The mode select switch is NOT depressed. At the 12 contact connector for the blade control handle, measure the resistance from the switch common contact 5 to the Normally Open contact 6. Repeat this measurement when the mode select switch IS depressed.
The mode select switch is NOT depressed. At the 12 contact connector for the blade control handle, measure the resistance from the switch common contact 5 to the Normally Closed contact 7. Repeat this measurement when the mode select switch IS depressed.Expected Result:For Step "C": When the mode select switch is NOT depressed, the resistance measurement should be above 5000 ohms.When the mode select switch IS depressed, the resistance measurement should be below 5 ohms.For Step "D": When the mode select switch is NOT depressed, the resistance measurement should be above 5 ohms.When the mode select switch IS depressed, the resistance measurement should be above 5000 ohms.Results:
OK - The resistance measurements are correct. The mode select switch is operating correctly. Proceed to Test Step 2.
NOT OK - The resistance measurements are not correct. The switch operation is not correct.Repair: The mode select switch is faulty. Replace the implement control handle.STOPTest Step 2. CHECK THE INPUT CIRCUITS FOR A SHORT TO +BATTERY
The key start switch and the disconnect switch remain in the OFF position.
The machine harness remains disconnected from the 12 contact blade control handle connector.
Disconnect the machine harness connectors J1 and J2 from the ECM.
At machine harness connector J1, measure the resistance from contact J1-63 (wire J943-GN) to all of the other J1 and J2 contacts.
At machine harness connector J2, measure the resistance from contact J2-54 (wire J944-BU) to all of the other J1 and J2 contacts.Expected Result:Each resistance measurement measure greater than 5000 ohms.Results:
OK - Each resistance measurement is greater than 5000 ohms. Proceed to Test Step 3.
NOT OK - Each resistance is not greater than 5000 ohms. Repair: There is a short in the machine harness. The short is between either wire J943-GN or wire J944-BU