768C, 769C, 769D, 772B, 773B, 773D, 776C, 777B, 777D, 784B, 785, 785B, 789, 789B, 793, 793B and 793C Off-Highway Truck/Tractors and 771C, 771D and 775D Quarry Trucks Automatic Retarder Control (ARC) System Caterpillar

Note: This procedure can cause new diagnostic codes to be recorded. Ignore these created diagnostic codes. Complete the following procedure. Then clear the created diagnostic codes.

1. CHECK THE SOLENOID.

   1. Turn the disconnect switch and the key start switch to the ON position. Do not start the engine. Put the display in the detected fault mode (mode 1). The CID 0711 FMI F05 fault will still be present.

   2. Ensure that the CID and the FMI for the solenoid is active.

   3. Place the parking brake switch in the OFF position.

   4. Disconnect the machine harness from the solenoid.

   5. At the machine harness connector for the solenoid that is being tested, install a jumper. The jumper should be installed from the signal contact wire (D988-WH-16) to the return contact wire (202-BK-16).

   6. Observe the status of the diagnostic code. The diagnostic code is active or the diagnostic code is NOT active.

      Expected Result: The status of the diagnostic code is active and the status of the diagnostic code is NOT active as the jumper is installed and then removed.

      Results:

      • OK: The circuit is correct. The solenoid or the machine harness is faulty. Repeat this test "CHECK THE SOLENOID" in order to verify the solenoid failure. STOP.

      • NO: The diagnostic code remains active. Proceed to Step 2.

2. CHECK THE SOLENOID CIRCUIT FOR AN OPEN.

   1. The jumper that is between the signal contact and the return wire remains installed.

   2. Turn the key start switch and the disconnect switch to the OFF position.

   3. Disconnect the machine harness connector A from the ARC.

   4. At the A machine harness connectors for the ARC, measure the resistance from the signal wire of the solenoid (D988-WH-16) to the frame ground. The resistance should be less than 5000 ohms.

      Expected Result: There should be a resistance of less than 5000 ohms resistance.

      Results:

      • OK: The measured resistance is less than 5000 ohms. The machine harness is correct. Proceed to Step 3.

      • NO: There is an open circuit in the machine harness. The open circuit is in the wire for the solenoid signal or in wire (K952-WH-16) of the machine harness. Repair the machine harness or replace the machine harness. STOP.

3. CHECK IF THE DIAGNOSTIC CODE REMAINS.

   1. The contacts of the harness connectors should be cleaned and inspected.

   2. Reconnect all of the harness connectors.

   3. Turn the disconnect switch and the key start switch to the ON position.

   4. Clear all of the inactive diagnostic codes.

   5. Operate the machine.

   6. Stop the machine and place the parking brake switch in the ON position.

   7. Observe the status of the diagnostic code. The diagnostic code is active or the diagnostic code is NOT active.

      Expected Result: The diagnostic code is NO longer active.

      Results:

      • OK: The diagnostic code is NO longer active. The diagnostic code does not exist at this time. The initial diagnostic code was probably caused by a poor electrical connection or a short at one of the harness connectors that was disconnected and reconnected. Resume normal machine operation. STOP.

      • NO: The diagnostic code has not been corrected. It is unlikely that the ARC is faulty. Exit this procedure and perform a check of the CID and the FMI again. Recheck the status of the diagnostic code. The diagnostic code may be active. If the cause of the diagnostic code is not found, replace the ARC. See Testing And Adjusting, "ARC - Replace". STOP.