ORIFICE 5I4277 - Caterpillar

Illustration 1 g01432629
Schematic for the Steering Wheel SensorThis diagnostic code is associated with the Steering Wheel Sensor. The code FMI 03 means that the Machine ECM has determined that the voltage of the circuit for the sensor is above normal.Note: The Machine ECM is located inside the Center Console mounted to the access door.The output frequency of the position sensor is approximately 500 hertz. The duty cycle of the signal changes as the position sensor moves. The duty cycle varies from 5 to 95 percent.A - Approximate position of 10 percent duty cycleB - Approximate position of 50 percent duty cycleC - Approximate position of 90 percent duty cycleThe possible causes of this diagnostic code are listed below:
The signal circuit for the sensor is open.
The signal circuit for the sensor is shorted to the +battery circuit.
The sensor has failed.
The power circuit or the ground circuit has failed.
The Machine 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 CID 0162 FMI 04 is active before performing this procedure.Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure.System Response:When this diagnostic code is active, the following occurs:
Machine does not come to a stop.
Machine speed is limited.
Machine will continue to propel.
The operator station fault lamp is active.Test Step 1. CHECK FOR POWER AT THE SENSOR.
Do not disconnect the harness connector from the sensor.
Turn the key start switch and the disconnect switch to the ON position.
At the back of the harness connector for the sensor, insert a 7X-1710 Multimeter Probe along the voltage supply wire (contact A).
Measure the voltage from contact A to frame ground.Expected Result:The voltage is 8.0 0.5 DCV.Results:
OK - The voltage is 8.0 0.5 DCV. Proceed to Test Step 2.
NOT OK - The voltage is not 8.0 0.5 DCV. The + battery circuit in the machine harness has failed.Repair: Replace the machine harness or repair the machine harness.STOPTest Step 2. CHECK FOR PROPER GROUND AT THE SENSOR.
The machine harness remains connected to the sensor.
Turn the key start switch and the disconnect switch to the OFF position.
Remove the 7X-1710 Multimeter Probe from the voltage supply wire (contact A).
At the back of the harness connector for the sensor, insert a 7X-1710 Multimeter Probe along the ground wire C234-BK (contact B).
Measure the resistance from contact B to frame ground.Expected Result:The resistance is less than 5 ohms.Results:
OK - The resistance is less than 5 ohms. The ground circuit is correct. Proceed to Test Step 3.
NOT OK - The resistance is greater than 5 ohms. The ground circuit in the machine harness has failed.Repair: Replace the machine harness or repair the machine harness.STOPTest Step 3. CHECK THE WIRING HARNESS OF THE SENSOR FOR AN OPEN CIRCUIT.
The key start switch and the disconnect switch remain in the OFF position.
Disconnect the machine harness from the sensor.
At the harness connector for the sensor,