HOSE 0858402 - Caterpillar

Illustration 1 g02807819
Location of the Steering Wheel Position Sensor
Illustration 2 g02807670
Steering Wheel Position Sensor Connections
This diagnostic code is associated with the Steering Wheel Position Sensor 1. The Steering Wheel Position Sensor is located on the LH Operator console.The FMI 08 diagnostic code is activated when the ECM determines that the signal frequency, or pulse width, is not within expected range.The Steer Position Sensor receives power from the Engine ECM 5 VDC power supply. This code relates to one of the two input signals to the Machine ECM 1 that will indicate the position of the steering control handle. In normal operation, one signal will lead the other signal by 45% duty cycle. When one signal is 25% duty cycle, the other will be 70% duty cycle for example.The position sensor sends the PWM input signal to the Machine ECM 1. The position sensor is a PWM sensor that operates at a frequency of approximately 200 40 Hz. The voltage of the signal ranges from 0.0 VDC to 5.0 VDC. The duty cycle of the signal will vary from 5 percent to approximately 95 percent when the control is rotated. Possible causes of this diagnostic code are:
Sensor power supply failure.
Sensor failure.
Intermittent or poor connections in the sensor circuit.
Machine ECM 1 failure. ECM failure is unlikely. Note: Poor connections are often the cause of a problem in electrical circuits. Before performing this procedure, inspect all the machine harnesses and connectors involved in the circuit. Make sure to verify that all of the connections in the circuit are clean, secure, and in good condition. Correct any problems found with any of the connections. Verify the diagnostic code CID 1471 FMI 08 is still active, before continuing with this procedure.Note: The following test procedure may create other diagnostic codes. Ignore all the created diagnostic codes now, but clear all those codes after the cause for the original diagnostic code has been corrected. Test Step 1. CHECK THE SENSOR DUTY CYCLE AND FREQUENCY.Turn the key start switch and the disconnect switch to the OFF position. Follow the safe power down procedure that is detailed at the beginning of this procedure.
At the machine harness side of the steering control connector, use a 151-6320 Removal Tool to remove the signal wire H752-YL(Yellow) and socket at contact 3 from the harness connector. The machine harness connector remains connected to the steering control connector.
At the vacant space in the machine harness connector where the signal wire was removed: use the positive side 7X-1710 Multimeter Probe to insert into the connector contact 3 to contact the signal pin on the steering control handle connector. Insert the other probe along the sensor return contact 2 (wire J843-BK(Black)). Ensure that a good contact is made between the probes and the sensor contacts.
Turn the disconnect switch and the key start switch to the ON position.
With the Steering Wheel stationary, measure the frequency of the signal from the sensor.
While observing the measurement, wiggle the Steering Wheel Position Sensor connector. Gently pull