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

This diagnostic code is recorded when the ARC does not receive an engine speed signal on the data link. This diagnostic code is also recorded when the signal is abnormal. The electronic engine control sends the engine speed signal to the ARC over the data link.

Note: The ARC will record a diagnostic code that is related to the data link CID 0248 after the ARC records a related CID 0190 FMI 09 diagnostic code.

Note: Ensure that the CID 0190 FMI 09 diagnostic code is active. The intermittent diagnostic code may be caused by a poor electrical connection of the data link if the diagnostic code is not present. Check the connectors of the harness.

1. INSPECT THE HARNESS CONNECTORS.

   1. Inspect the connections of the machine harness that are related to the data link.

   2. Make sure that the connectors are clean and tight. Repair the machine harness or replace the machine harness.

   3. 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      Expected Result: The diagnostic code is NO longer active.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      • OK: The diagnostic code is NO longer active.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 is NOT present at this time. The circuits of the data link may have an intermittent connection in the machine harness. Watch for a recurrence of this diagnostic code. STOP.

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

2. CHECK THE DATA LINK CIRCUIT.

   1. Use the Electrical System Schematic in the Service Manual of the machine in order to check the circuits of the data link. Check the circuit in the machine harness for continuity and shorts.

   2. Check wires 893-GN-16 and 892-BR-16 of the machine harness for continuity and shorts. Check from the ARC to the electronic engine control.

      Expected Result: The circuit of the data link in the machine harness is correct.

      Results:

      • OK: The data link circuit in the machine harness is correct. The ARC and/or the electronic engine control are not likely to be causing the diagnostic code. Check the diagnostics of the electronic engine control. Troubleshoot any diagnostic codes that are related to the data link. Replace the ARC if the cause of the diagnostic code is not found. See Testing And Adjusting, "ARC - Replace". STOP.

      • No: The data link circuit in the machine harness is faulty. Repair the machine harness or replace the machine harness. STOP.