Water Delivery System and 777F WTR, 777G WTR and 785D WTR OEM Off-Highway Trucks Caterpillar

The data link error diagnostic code is recorded when the WDS display loses contact with the machine J1939 network stream. This stream supplies the status of the truck for RPM, ground speed, and transmission gear. Without these values the truck cannot spray the required amount of water correctly. As a result, the system is shut down and the data link error diagnostic code is logged.

Illustration 1	g03610786

Illustration 2	g03643614

The possible causes of the data link error are listed below:

• Electrical harness damage

• Failed connection at the Chassis Control ECM

• Failed connection at the Brake Control ECM

• Failed WDS display

1. Check Electrical Harness

   1. Park the machine. Turn key start switch to the OFF position.

   2. Turn the machine disconnect to the OFF position.

   3. Remove wire Y959-YL(Yellow)from pin "C1-10" and remove wire Y960-GN(Green)from pin "C1-3" on the MD3 display.

   4. Remove wire Y959-YL(Yellow)from pin "J2-64" and remove wire Y960-GN(Green)from pin "J2-65" on the Brake ECM (777G) or cab controller (785D).

   5. Check the continuity of wires Y959-YL(Yellow)and Y960-GN(Green).

      Expected Results: Both wires should read between 0-9 Ohms.

      Results:

      OK - Both wire read less than 9.0 Ohms. Proceed to Step 2.

      Not OK - If either wire reads more than 9.0 Ohms resistance, then the harness has failed.

      Repair: Find the harness damage and repair or replace wires Y959-YL(Yellow)and Y960-GN(Green)with a new twisted pair from the cab controller (785D) or AUX connector ( 777F/ 777G) to the WDS Display.

2. Check Cab Controller (785D Only)

   1. Park the machine. Turn key start switch to the ON position.

   2. Connect the 317-7485 COM Adapter 3.
      Show/hide table

      Illustration 3	g03643690

   3. Using the Cat composer tool to inspect the service parameters for engine output speed, vehicle speed, and actual gear.

      Expected Result: The parameters represent the trucks current state of operation.

      Results:

      OK - All parameters represent the trucks current state of operation. Proceed to Step 3.

      Not OK - One or more of the parameters states "Data Error" in the Valve column.

      Repair: Check CDL wires on cab controller ECM. Wire 893-GN(Green)from pin "J1-20" and wire 892-YL(Yellow)from pin "J1-20" should be continuous from the cab controller to the machine chassis ECM. Find the harness damage and repair or replace wires.

      Result: Check the EOS, TOS, and shift lever position in the electronic technician tool. Ensure that the truck is not having a malfunction with one or all of these parameters. The malfunction may be due to a sensor error or wiring error on the factory machine configuration.

      Not OK - The cab control ECM will not respond the Cat composer tool and is verified to have proper power and ground connections.

      Result: Replace the cab control ECM and program the ECM with software 382-8036 Software V04.

3. Check WDS Display

   1. Park the machine. Turn key start switch to the OFF position.

   2. Turn the machine disconnect to the OFF position.

   3. Turn the machine disconnect back to the ON position.

   4. Turn key start switch to the ON position.
      Show/hide table

      Illustration 4	g03643761

   5. Check for any "No contact" errors.

      Expected Result: No errors should appear on the screen and no Datalink Error should be present.

      Results:

      OK - The machine is operating normally.

      Not OK - Multiple modules showing a "No contact" error, all previous tests have checked OK, and the Datalink Error is persistent .

      Repair: Replace the WDS display and program the display with the most up-to-date software.

      STOP.