247B, 257B, 267B, 277B and 287B Multi Terrain Loaders and 216B, 226B, 232B, 236B, 242B, 246B, 248B, 252B, 262B and 268B Skid Steer Loaders Auxiliary Hydraulic Electronic Control System Caterpillar

The two speed switch activates the two speed function. When the two speed function is activated, the indicator for the two speed will illuminate.

Illustration 1	g01035773
Schematic of the switch circuit for the two speed

Test Step 1. CHECK FOR PROPER OPERATION

1. Enable the machine.

2. Depress the two speed switch.

Expected Result:

The indicator for the two speed should illuminate.

Results:

• OK - The indicator for the two speed illuminates.

  Repair: The switch is operating correctly.

  Stop.

• NOT OK - The indicator for the two speed does not illuminate. Proceed to Test Step 2.

Test Step 2. CHECK THE STATUS OF THE SWITCH

1. Depress the two speed switch.

2. Observe the status on the Caterpillar ET.

3. Release the switch.

4. Observe the status on the Caterpillar ET.

Expected Result:

The switch status should have changed from the "CLOSED" status to the "OPEN" status.

Results:

• OK - The status of the switch changed from the "CLOSED" status to the "OPEN" status.

  Repair: The switch is operating correctly.If the two speed function is not operating, check the solenoid circuit.

  Stop.

• NOT OK - The switch status did not change from the "CLOSED" status to the "OPEN" status. Proceed to Test Step 3.

Test Step 3. CHECK THE CONTINUITY OF THE SWITCH

1. Locate the switch connector harness for the two speed circuit beneath the left hand joystick through the access panel.

2. Unplug the switch connector harness.

3. Press the switch.

4. Measure the resistance from contact 7 to contact 10 of the switch side of the connector.

Expected Result:

The resistance should be less than 5 Ohms.

Results:

• OK - The resistance is less than 5 Ohms. Proceed to Test Step 4.

• NOT OK - The resistance is greater than 5 Ohms.

  Repair: The switch has failed. Replace the joystick.

  Stop.

Test Step 4. CHECK THE SWITCH CIRCUIT

1. Reinstall the connector for the switch.

2. Remove the floorplate in order to get to the ECM.

3. Remove the wire harness from the ECM.

4. Press the switch.

5. Measure the resistance from contact 3 to contact 29 of the wiring harness connector.

Expected Result:

The resistance should be less than 5 Ohms.

Results:

• OK - The resistance is less than 5 Ohms.

  Repair: The ECM is very unlikely to have failed. Reconnect all connections and visually inspect the wire harness. Verify that the values that are present on the machine configuration screen match the machine's options. Verify that the values that are present on the machine configuration screen are installed correctly. Verify that the diagnostic code still exists. If the diagnostic code still exists perform the test steps again.Replace the ECM, if the cause of the diagnostic code was not found after the second attempt. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace".

  Stop.

• NOT OK - The resistance is greater than 5 Ohms.

  Repair: The circuit is open in the wire harness and/or the connector. Repair the wire harness and/or the connector or replace the wire harness and/or the connector.

  Stop.