PISTON AS 3232433 - Caterpillar

Illustration 1 g01158687
Schematic of the Position Sensor (Lift Cylinder) Note: The lift cylinder position sensor is equipped on the 824H and the 826H model machines that have the Automatic Blade Position function.This diagnostic code is associated with the lift cylinder position sensor. The FMI 08 means that the ECM has determined that the signal frequency or the signal pulse width is not within the expected range. The output frequency of the position sensor is approximately 115 hertz. The duty cycle of the signal changes as the position sensor moves. The duty cycle varies from 5 to 95%. The possible causes of this diagnostic code are listed below:
Intermittent connections or poor connections.
A wiring problem in the machine harness.
The sensor has failed.
Mechanical devices are loose.
The ECM has failed. This is unlikely.Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure. System Response:The machine response is listed:
The ABP function, the lockouts, cylinder snubbing and the blade float function will not operate.Note: Before performing this procedure, ensure that the lift cylinder position sensor is mounted correctly and securely on the end of the cylinder. After checking the sensor mount, ensure that this diagnostic code is still active before performing this procedure.Note: The following test procedure may create other diagnostic codes. Clear the logged diagnostic code after this procedure is completed.Test Step 1. CHECK THE DUTY CYCLE OF THE POSITION SENSOR
Do not disconnect the harness connector from the position sensor.
Turn the key start switch to the ON position.
At the back of the harness connector for the position sensor, insert a 7X-1710 Multimeter Probe in the connector between contact B (wire 299-BK) and contact C (wire A428-GN).
While raising and lowering the implement, measure the duty cycle and the frequency of the output signal. The correct limits for the duty cycle are given at the start of this procedure.Expected Result:The duty cycle and the frequency of the sensor signal are within the acceptable limits.Results:
YES - The duty cycle and the frequency of the sensor signal are correct. The position sensor is not the cause of the diagnostic code. Proceed to Test Step 2.
NO - Either the duty cycle or the frequency of the sensor signal are NOT within the acceptable limits. The position sensor is faulty.Repair: Replace the position sensor. Stop.Test Step 2. INSPECT THE SENSOR HARNESS CONNECTIONS
Turn the disconnect switch to the OFF position.
Refer to the machine electrical system schematic for your machine. Inspect all harness connections that are involved in the circuit for the position sensor. Ensure that the connectors are intact, clean and tight.
Check the connectors for proper mating. Ensure that all the seals are present and in place.
Check the harness for signs of damage or abrasion.
Check the wires at the connector. Ensure that the wires are secured tightly into the connector. Take care not to pull the wire out of the connector.
Check the exposed wires at the connectors for nicks or signs of abrasion.
Check for moisture inside the connector.
Check the connectors for dirty contacts or corroded contacts.
Check each pin and