TH220B, TH330B, TH340B, TH350B, TH355B, TH360B, TH460B, TH560B and TH580B Telehandlers Caterpillar

Illustration 1	g00903977
Schematic for the Auto/Manual Switch

The transmission auto/manual switch has two inputs to the machine electronic control module (ECM). During normal operation, one input is grounded while the other input is open. The valid combination for each switch position is shown in table 1 that follows. If an invalid combination is detected by the ECM, a circuit failure is present. The diagnostic code is recorded when the inputs for the switch are grounded. The diagnostic code is set in 5 seconds. After the problem has been corrected, the diagnostic code will be clear within 1 second.

Note: Ensure that the desired diagnostic code is active.

Before performing this procedure, refer to table 1 in order to determine the connector that corresponds to the failed circuit and the contact that corresponds to the failed circuit.

Note: The following procedure can create other diagnostic codes that can be detected by the ECM. Ignore these created diagnostic codes and clear the created diagnostic codes when this diagnostic code is corrected.

Possible causes of this diagnostic code are listed:

• The harness has failed.

• The switch has failed.

System Response:

The machine response is listed:

• The autoshift is disabled.

Test Step 1. CHECK FOR AN OPEN CIRCUIT.

1. Ensure that the diagnostic code is active.

2. Observe the ON/OFF status of the diagnostic code.

3. Disconnect the connector of the auto/manual switch from the machine harness.

Expected Result:

The active diagnostic code changes from "04" to "03" or No code will be present.

Results:

• YES - The auto/manual switch or the harness of the auto/manual switch has failed. Perform Step 1 again in order to verify the failure of the switch.

  Repair: Repair the switch or replace the switch if the switch has failed. Repair the switch or replace the switch harness if the switch harness has failed.

  Stop.

• NO - The auto/manual switch is not the cause of the failure. Proceed to Test Step 2.

Test Step 2. CHECK THE HARNESS CIRCUIT.

This test checks the continuity of the entire harness circuit that has failed. The auto/manual switch which was previously checked in Step 1 is included in this test.

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

2. Reconnect the auto/manual switch to the machine harness.

3. Disconnect the machine harness from the ECM.

4. At the machine harness connector for the ECM, check the continuity to ground of the open contacts and the grounded contact for each position of the auto/manual switch. Activate and deactivate each position of the auto/manual switch. Refer to table 1 for the correct status of the switch inputs.

Expected Result:

The continuity check does not agree with table 1.

Results:

• YES - The continuity check does NOT agree with the previous table. The harness circuit has failed. There is a short to ground in the machine harness between the ECM and the switch.

  Repair: Repair the machine harness or replace the machine harness.

  Stop.

• NO - The continuity check agrees with the previous table. The harness circuit is correct. It is unlikely that the ECM has failed. Exit this procedure and perform CID 0368 FMI 04 again.

  Repair: If the cause is not found, replace the ECM. Refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace" for more information on replacing the ECM.

  Stop.