HARNESS AS-WIRING 3591245 - Caterpillar

Illustration 1 g01334039
Connections of Blade "Left Constant Downforce Control Position" sensor
This diagnostic code is associated with the blade "left constant downforce control position" sensor. The FMI 08 means that the Implement ECM has detected that the voltage or the duty cycle of the position sensor signal frequency or the signal pulse width is not within the expected range. The position sensor is connected to the "left downforce operator control dial". The position sensor will supply a PWM duty cycle input to the Implement ECM in order to indicate the position of the dial. The position sensor operates in a frequency range of approximately 400 hertz to 600 hertz. When the "blade downforce dial" is moved to the full clockwise position (no downforce), the PWM duty cycle of the signal is approximately 93 percent. When the dial is moved through a detent to the full left counterclockwise position (maximum downforce), the PWM duty cycle of the signal is approximately 10.6 percent.The conditions that could cause this diagnostic code to activate are listed below:
The sensor has failed.
Intermittent connections or poor connections in the circuit of the sensor signal.
The ECM has failed. This is unlikely.Note: Note: Before performing this procedure, inspect the harness connectors that are involved in the circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, that all connections are secure and that all connections are in good condition. If 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. Ignore these created diagnostic codes and clear the diagnostic codes when the problem has been corrected.Test Step 1. CHECK THE DUTY CYCLE AND THE FREQUENCY OF THE SIGNAL AT THE SENSOR
Turn the key start switch and the disconnect switch to the OFF position.
At the connector for the sensor of the machine harness, use a 151-6320 Removal Tool to remove the signal wire H786-YL(Yellow) and the socket at contact C from the harness connector. The machine harness connector remains connected to the connector for the position sensor.
At the back of the sensor connector, insert 7X-1710 Multimeter Probes along the sensor signal contact C and the return contact at B.
Turn the disconnect switch and the key start switch to the ON position.
Measure the duty cycle and the frequency of the sensor at the contact for the sensor connector C and B. Move the "downforce control dial" through the full range of movement. Expected Result:For dial operation, the position sensor duty cycle is in the range of 10.6 percent when the dial is in the full counterclockwise position to 93 percent when the dial is in the full clockwise position (the frequency of the sensor is expected to be approximately 500 hertz).Results:
OK - The duty cycle of the sensor is correct. The sensor is not the problem. Reconnect the wire and the socket that