COOLER ASP 4662337 - Caterpillar

Illustration 1 g01735873
Steering Control Position Sensor 1 connectionsTwo steer position sensors are required for correct operation of the steering control. The steer position sensors are located in the Speed/Direction Handle. Each sensor provides an input signal to the Machine ECM that will indicate the position of the steering control handle. The FMI 04 diagnostic code is activated when the ECM detects that the signal voltage from the Steer Position Sensor 1 is below the acceptable range. The Steer Position Sensor 1 receives power from the Machine ECM 8 volt power supply circuit and the 8 V return circuit.The position sensor is a PWM sensor that operates at a frequency of approximately 500 Hz. The position sensor sends a PWM input signal to the Machine ECM. The duty cycle of the signal will vary from approximately 10 percent when the steering control handle is at the full left position to approximately 90 percent when the steering control handle is at the full right position. When the steering control handle is at the center position, the duty cycle will be approximately 50%.The possible causes of this diagnostic code are listed:
The signal circuit is shorted to a ground source.
The sensor has failed.
The ECM has failed. This is unlikely. Note: Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, secure and 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 SENSOR
Turn the disconnect switch and the key start switch to the ON position. DO NOT START THE ENGINE.
Disconnect the machine harness connector from the