279C, 279C2, 289C, 289C2 and 299C Compact Track Loaders, 287C, 277C, 277C2, 287C2 and 297C Multi Terrain Loaders and 246C, 256C, 262C, 262C2 and 272C Skid Steer Loaders Machine Electronic Control System Caterpillar

Illustration 1	g01269296
Schematic of the Implement Lockout Switch

This diagnostic code is recorded when the status of both the normally open inputs and normally closed inputs are grounded. This switch has two inputs to the ECM. The inputs are normally open and normally closed. During proper operation, one input is open and the other input is grounded.

The possible causes of this diagnostic code are listed:

• The normally open circuit is shorted to ground while the normally closed circuit is grounded through the switch.

• The normally closed circuit is shorted to ground while the normally open circuit is grounded through the switch.

• The normally open circuits and the normally closed circuits are shorted to ground in the harness.

• The normally open circuits and normally closed circuits are shorted together. The switch must be in one specific position.

• The switch has failed.

System Response:

The machine response is listed:

• The implements will not work.

Table 1 contains wire numbers and connector contacts. Use this information to troubleshoot the failed circuit.

Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the original diagnostic code is corrected.

Ensure that the diagnostic code is active.

Test Step 1. CHECK THE SWITCH.

1. Observe ON/OFF status of the diagnostic code indicator.

2. Disconnect the connector of the switch from the harness.

Expected Result:

The diagnostic code remains active.

Results:

• YES - The diagnostic code remains active. The switch is not the cause of the diagnostic code. Proceed to test step 2 .

• NO - The diagnostic code is inactive. The switch has failed or the harness has failed.

  Repair: Repeat this test in order to verify the failure of the switch. Repair the switch or replace the switch. Repair the harness or replace the harness.

  STOP

Test Step 2. CHECK THE HARNESS CIRCUIT.

1. This test checks the continuity of the entire harness circuit that has failed. This test includes the switch that was previously checked.

2. Reconnect the switch that was disconnected in the previous step.

3. Disconnect the harness from the ECM.

4. Activate the switch. At the harness connector for the ECM, check the continuity to ground of the normally closed contact and the normally open contact.

Expected Result:

The continuity agrees with table 1.

Results:

• YES - The continuity agrees with the values in the preceding table. The harness circuit is correct.

  Repair: It is unlikely that the ECM has failed. Exit this procedure and perform this troubleshooting procedure again. If the cause of the diagnostic code is not found, replace the ECM. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace".

  STOP

• NO - The continuity check DOES NOT agree with values in the preceding table.

  Repair: The harness circuit has failed. There is a short to ground in the harness between the ECM and the switch. Repair the harness or replace the harness.

  STOP