515 Wheel Skidder and 525 Wheel Skidder Transmission and Grapple Electronic Control System Caterpillar

Illustration 1	g00528540
Schematic of the Tong Auto/Manual Switch (1) Tong auto/manual switch. (2) Transmission and grapple Electronic Control Module (ECM).

When the transmission and grapple ECM detects a ground signal from the tong auto/manual switch, the ECM enables the tong auto close function. In order to enable the tong auto close function, the ECM must be receiving an engine oil pressure signal via the CAT Data Link. After being enabled, the ECM activates the function when the CLOSE position of the tong position switch is pressed (momentarily pressed and released). The tong auto indicator will be turned ON at this time. This shows that the function is activated on the Caterpillar Monitoring System.

The tong auto close function is deactivated when any of the following conditions occur:

• The operator presses the OPEN position of the tong position switch.

• The operator presses the CLOSED position of the tong position switch for a minimum of one second.

• The operator presses the MAN position of the tong auto/manual switch.

• The engine oil pressure signal that is sent from the Caterpillar Monitoring System is low.

• The ECM detects a fault that is related to the grapple control function.

Note: If the manual mode of the tongs does not function, troubleshoot the related systems first. If the cause of the fault is electrical, the ECM should have recorded the fault. Refer to Testing and Adjusting, "Troubleshooting Service Codes" for more information. If the engine oil pressure indicator on the Caterpillar Monitoring System is flashing, the AUTO mode will not function.

Problem

The tong auto close function is not operating correctly with the tong auto/manual switch in the AUTO position.

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

2. Disconnect tong auto/manual switch (1) from the machine harness connector.

3. Check tong auto/manual switch (1) for continuity. There should be continuity in the AUTO position and no continuity in the MANUAL position.
   • The switch operates correctly. Proceed to Step 4.

   • The switch does not operate correctly. Replace the tong auto/manual switch. STOP.

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

5. Reconnect the machine harness connector to tong auto/manual switch (1). Disconnect the machine harness connector from the ECM.

6. Place the tong auto/manual switch (1) in the AUTO position.

7. At the machine harness connector for the ECM, check for continuity between contact 28 (wire F838-BR) and contact 2 (wire 202-BK).

8. There should be continuity in the AUTO position and no continuity in the MANUAL position.
   • The continuity is correct. Proceed to Step 9.

   • The continuity is not correct. The machine harness is open between tong auto/manual switch (1) and the transmission and grapple ECM. Replace the machine harness or repair the machine harness. STOP.

9. Reconnect the machine harness to the transmission and grapple ECM. Recheck the operation of tong auto/manual switch (1) .
   • The problem remains. Proceed to Step 10.

   • The problem is no longer present. The initial problem was probably caused by a poor electrical connection at one of the harness connectors. Resume normal machine operation.

10. Check the Caterpillar Monitoring System for a CAT Data Link fault.

• A CAT Data Link fault exists. Refer to the Service Manual module, Service Manual, SENR6717, "Caterpillar Monitoring System" for more information about the CAT Data Link.

• A CAT Data Link fault is not present. It is unlikely that the transmission and grapple ECM is faulty. Perform the previous steps again. If the cause of the problem is not found, replace the ECM. Refer to Testing and Adjusting, "Electronic Control Module (Transmission and Grapple) - Replace" for more information on replacing transmission and grapple Electronic Control Module (ECM).