CONTROL GP-HYDRAULIC PEDAL 3935477 - Caterpillar

Illustration 1 g02010133
Schematic of the Front Brake Oil Pressure Sensor
Sales model 854G/992G
This diagnostic code is associated with the Front Brake Oil Pressure Sensor. The FMI 08 diagnostic means that the "ECM" has determined that the signal frequency or the signal pulse width is not within the expected range. This PWM sensor operates within a frequency range of 350 to 650 hertz. The sensor has a minimum operating duty cycle of 10% 5% and a maximum operating duty cycle of 90% 5%. 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: 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. Clear any created diagnostic codes after the original diagnostic code has been corrected.Note: Use a Digital Multimeter for the measurements in this procedure. System Response:A Level 1 warning will be generated. The feature is disabled.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 7X-1710 Multimeter Probe along contact A (wire K983-BU(Blue)) for the voltage supply.
At the back of the harness connector for the sensor, insert a 7X-1710 Multimeter Probe along contact B (wire J842-BK(Black)) for the ground.
Turn the starter keyswitch and the disconnect switch to the ON position.
Measure the voltage from contact A (wire K983-BU(Blue)) to contact B (wire J842-BK(Black)). Expected Result:The voltage is 8 0.5 VDC.Results:
OK - The voltage is 8 0.5 VDC. Proceed to Test Step 3.
NOT OK - The voltage is not 8 0.5 VDC. 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 starter keyswitch and the disconnect switch to the OFF position.
At the back of the harness connector for the sensor, remove the 7X-1710 Multimeter Probe from contact A and insert the probe along the wire contact point for the signal voltage C (wire C456-OR(Orange)).
The other 7X-1710 Multimeter Probe remains at the ground wire contact B (wire J842-BK(Black)).
Turn the disconnect switch and the starter keyswitch to the ON position.
Monitor the signal of the sensor with the 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. Expected Result:The sensor's signal responds in the manner that is described at the beginning of this procedure.Results:
OK - The sensor's signal responds correctly. The