DISC 2384684 - Caterpillar

Illustration 1 g02316933
Connections for "Steering Position Sensor 2"
Three steering position sensors are required for correct operation of the steering control lever. The steering position sensors are located in the left assembly of the joystick. Each sensor provides an input signal to the "Implement ECM 2" and to the "Transmission/Chassis ECM". This diagnostic code is activated when the ECM detects that the signal voltage from the "Steering Position Sensor 2" is below normal. The "Steering Position Sensor 2" receives power from the 8 VDC power supply of the "Implement ECM 2". The sensor is internally connected to the ground through the 8 VDC sensor return of the "Transmission/Chassis ECM" and the "Implement ECM 2". The steering sensor must lose both grounds in order to lose a ground connection. The illustration above indicates the power and ground connections for the "Steering Sensor 2".The position sensor is a PWM sensor that operates at a frequency of approximately 500 80 Hz. The position sensor sends a PWM input signal to the "Implement ECM 2" and to the "Transmission/Chassis ECM". The duty cycle varies from 10 5% at full left position to 90 5% at full right position. When the joystick is in the center position, the duty cycle will be approximately 50%.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: The "Transmission/Chassis ECM" (MID 027) and the "Implement ECM 2" (MID 145) receive an input signal from the "Steering Sensor 2". Both ECM modules can activate a CID 1472 FMI 04 diagnostic code when the signal voltage is below normal. If one ECM has activated a CID 1472 FMI 04 diagnostic code and the other ECM has 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, either ECM is unlikely to be the cause of the problem. For either condition, proceed with this procedure in order to verify the cause of the problem.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 and clear the diagnostic codes when the problem has been corrected.Test Step 1. USE CAT ET TO CHECK FOR SIMILAR DIAGNOSTIC CODES
Locate a laptop computer that is loaded with the latest version of Cat ET.
Connect