FORK 6B9562 - Caterpillar

Illustration 1 g01362188
Connections of the shift lever position sensorThis diagnostic code is associated with the shift lever position sensor. The FMI 8 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 500 hertz. The value of the sensor's duty cycle is approximately 50% in the neutral position. The duty cycle of the signal increases as the lever is moved from the neutral position to the forward position. The value of the sensor's duty cycle is approximately 80% 10% in the forward position. The duty cycle of the signal decreases as the lever is moved from the neutral position to the reverse position. The value of the sensor's duty cycle is approximately 20% 10% in the reverse position. The possible causes of this diagnostic code are listed below:
The sensor has failed.
Intermittent connections or poor connections
Mechanical devices are loose.
The ECM has failed. This is unlikely.Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of SPN 525 FMI 8 is active before performing this procedure.Note: Use the digital multimeter for the measurements in this procedure. System Response:The transmission will be placed in NEUTRAL until the diagnostic code is cleared.Test Step 1. CHECK FOR POWER AT THE SENSOR.
Do not disconnect the harness connector from the sensor.
At the back of the harness connector for the sensor, insert a multimeter probe along the voltage supply wire (contact 1).
Turn the key start switch and the disconnect switch to the ON position.
Measure the voltage from contact 1 to frame ground.Expected Result:The voltage is 10 DCV.Results:
OK - The voltage is 10 DCV. Proceed to Test Step 3.
NOT OK - The voltage is not 10 DCV. The circuit is open. Repair: Repair the machine harness or replace the machine harness.STOPTest Step 2. CHECK THE SIGNAL CIRCUIT OF THE SENSOR.
Turn the key start switch and the disconnect switch to the OFF position.
At the back of the harness connector for the sensor, remove the multimeter probe from contact 1 and insert the probe along the signal wire (contact 3).
At the back of the harness connector for the sensor, insert the multimeter probe along the ground wire (contact 2).
Turn the disconnect switch and the key start switch to the ON position.
Monitor the signal of the sensor with the digital multimeter.
Without disconnecting the sensor or the hardware that is associated with the sensor from the machine, take the sensor through the full operating range of the sensor.Note: On some machines, it may be necessary to start the engine in order to take the sensor through the full operating range of the sensor.Expected Result:The sensor's signal responds in the manner that is described at the begining of this procedure.Results:
OK