854G and 854K Wheel Dozers and 992G, 992K and 994F Wheel Loaders VIMSTM Caterpillar

Illustration 1	g01994654
Schematic of the Lift Linkage Position Sensor Sales model 854K/992K

This diagnostic code is recorded when the ECM records a signal from the position sensor for the lift linkage that has an abnormal frequency, abnormal pulse width or an abnormal period. The position sensor is Pulse Width Modulation (PWM). The signal wire for the sensor connects to contact J1-29 (wire C530-BU(Blue)) of the ECM.

The possible causes of this diagnostic code are listed:

• The circuit for the +battery to the sensor has an intermittent connection.

• The return circuit from the sensor has an intermittent connection.

• The signal circuit from the sensor has an intermittent connection.

• The sensor has failed.

Note: Ensure that the diagnostic code is active and that the diagnostic code indicator is active.

Note: The following procedure can create numerous related diagnostic codes. Reconnect all harnesses. Then, the related diagnostic codes will be shown as being NOT active. Complete the following procedure. Then, clear all of the related diagnostic codes.

System Response:

The machine response is listed:

• Implement features will not work.

Test Step 1. CHECK THE SENSOR

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

2. Disconnect the harness from the sensor.

Expected Result:

The diagnostic code indicator is active.

Results:

• OK - The diagnostic code indicator is active. This indicates that the diagnostic code remains active. The sensor is not causing the diagnostic code. Proceed to Test Step 2.

• NOT OK - Diagnostic code indicator is inactive.

  Repair: This indicates that the diagnostic code is gone. The sensor has failed. Replace the sensor.

  STOP

Test Step 2. CHECK THE HARNESS

1. The sensor remains disconnected from the harness.

2. The disconnect switch remains in the OFF position.

3. Disconnect the harness from the ECM.

4. At the harness connector for the ECM, measure the resistance between signal contact C (wire C530-BU(Blue)) and frame ground.

Expected Result:

The resistance is greater than 5000 Ohms.

Results:

• OK - The resistance is greater than 5000 Ohms.

  Repair: The harness circuit resistance is correct. It is unlikely that an ECM has failed. Exit this procedure and perform this test step again. If the diagnostic code is not found, replace the ECM. See Testing and Adjusting, "Module - Replace".

  STOP

• NOT OK - The resistance is less than 5000 Ohms.

  Repair: The harness has failed. There is a short between frame ground and the signal circuit in the harness. Repair the harness or replace the harness.

  STOP