JOINT AS 2751952 - Caterpillar

Illustration 1 g02365116
Connections of "Left Steering Cylinder" position sensor
This diagnostic code is associated with the "Left Steering Cylinder" position sensor. The position sensor provides a PWM input signal to the "Transmission/Chassis ECM" and to the Implement ECM 2. The FMI 04 diagnostic code is activated when the ECM reads the sensor input signal and the voltage of the signal is below normal.The sensor is a PWM sensor that operates at a frequency of approximately 500 Hz. The duty cycle of the PWM signal that is supplied to the ECM is measured in small increments. The changes in the duty cycle of the sensor cannot be measured with a digital multimeter.The possible causes of this diagnostic code are listed below:
The signal circuit is shorted to a ground source.
The sensor has failed.
The ECM has failed. A failure of the Transmission/Chassis ECM is unlikely. Note: Before performing this procedure, check for an active CID 1482 diagnostic code for the 10 VDC sensor power supply of the "Transmission/Chassis ECM". Correct any problem with the 10 VDC power supply before performing this procedure.Note: The "Transmission/Chassis ECM" (MID 027) and the Implement ECM 2 (MID 145) receive an input signal from the "Left Steering Cylinder" position sensor. Both ECM modules can activate a CID 2200 FMI 04 diagnostic code when the signal is below normal. If one ECM is communicating an active CID 2200 FMI 04 diagnostic code and the other ECM is not, the sensor is probably operating correctly. When this condition occurs, a poor connection in the machine harness would be suspected. When both ECM modules have activated the diagnostic code, either the sensor or a harness problem could be the cause. If both ECM modules have activated the diagnostic code, it is very unlikely that either ECM is the cause of the problem. For either condition, proceed with this procedure in order to verify the cause of the problem.Note: Before performing this procedure, inspect the harness connectors that are involved in the circuit. Poor connections are often 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 and clear the diagnostic codes when the original diagnostic code has been corrected.Test Step 1. CHECK THE SENSORTurn the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness connector from the "Left Steering Cylinder" position sensor and disconnect the machine harness connector from the "Right Steering Cylinder" position sensor. Mark the harness connector for the "Left Steering Sensor".
Connect the marked connector for the "Left Steering Sensor" to the connector for the "Right Steering Sensor" . Connect the unmarked connector for the "Right Steering Sensor" to the connector for the "Left Steering