ENGINE AR 2228187 - Caterpillar

Illustration 1 g06033973
Connections of the Lift Linkage Position Sensor
CID 350 FMI 04 is associated with the Lift Linkage Position Sensor that is located in the lift arm assembly. The position sensor provides a Pulse Width Modulated (PWM) input signal to the Machine Electronic Control Module (ECM). The FMI 04 diagnostic code is activated when the Machine ECM reads the input signal from the sensor and the voltage is below normal.The sensor is a PWM sensor that operates at a frequency of approximately 500 100 Hz. The duty cycle of the PWM signal that is supplied to the ECM is measured in small increments. The changes in the duty cycle of the sensor cannot be measured with a digital multimeter.The following conditions could cause this diagnostic code to be activated:
The signal circuit is shorted to a ground source
The sensor has failed
The ECM has failed. The ECM is unlikely to failBefore performing this procedure, inspect the harness connectors that are involved in the circuit. Poor connections are often the cause of a problem in an electrical circuit. Inspect the connections for the following:
Connections are clean
Connections are secure
Connections are in good conditionIf a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure.Note: The following test procedure may create other diagnostic codes. Clear the diagnostic codes when the original diagnostic code has been corrected.Test Step 1. Check The Sensor
Turn the disconnect switch and the key start switch to the ON position. Do not start the engine.
Disconnect the machine harness connector from the Lift Linkage Position Sensor. Observe the status of the active CID 350 FMI 04 diagnostic code.Expected Result:The status of the CID 350 FMI 04 diagnostic code did not change when the position sensor was disconnected. A CID 350 FMI 03 diagnostic code has not been activated by the ECM. The CID 350 FMI 04 diagnostic code remains active when the sensor disconnected.Results:
YES - The CID 350 FMI 04 diagnostic code remains active when the sensor is disconnected. The sensor is not the cause of the problem. Proceed to Test Step 2.
NO - The status of the CID 350 FMI 04 diagnostic code is no longer active when the sensor was disconnected. The CID 350 FMI 03 diagnostic code is activated by the ECM when the Lift Linkage Position Sensor is disconnected. The machine harness and ECM are operating correctly.Repair: The operation of the Lift Linkage Position Sensor is the cause of the problem. Replace the Lift Linkage Position Sensor. After replacement of the sensor, verify that the operation is correct before operating the machine.STOPTest Step 2. Check The Signal Circuit For A Short To Ground
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness connector from the Linkage Position Sensor.
Disconnect the J1 machine harness connectors from the Machine ECM.
At machine harness connector J1 for the Machine ECM, perform the following:
Measure the resistance between signal contact J1-63 (wire C530-YL(Yellow)) and frame ground
Measure the