COVER 1776628 - Caterpillar

Illustration 1 g02712025
Schematic of the Steering Pilot Oil Pressure Sensor
This diagnostic code is recorded when the ECM reads the input signal from the Steering Pilot Oil Pressure Sensor and the PWM duty cycle is above normal.The sensor is a PWM sensor that operates at a frequency of approximately 500Hz 100Hz. The sensor sends a PWM input signal to the ECM. The duty cycle of the signal will vary from 3% to 97%.The possible causes of this diagnostic code are listed below:
There is an open in the sensor circuit.
The signal circuit is shorted to another circuit.
The sensor has failed.
The ECM has failed. This condition is unlikely.System Response:
The events related to this sensor signal will not work properly.Note: If a CID 0041 diagnostic code for the 8 VDC power supply has been activated, correct the problem before proceeding with this procedure.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 and clear the diagnostic codes when the problem has been corrected.Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure.Test Step 1. CHECK THE POWER SUPPLY OF THE SENSOR CIRCUIT
Turn the disconnect switch and the key start switch to the ON position.
At the pressure sensor harness connector, insert 7X-1710 Multimeter Probes along the power supply contact 1 wire X800-OR(Orange)and along ground contact 2 wire X998-BR(Brown).
Do not disconnect the machine harness from the connector.
Measure the DC voltage of the sensor power supply.Expected Result:The voltage measurement is approximately 8 VDC 0.4 VDC.Results:
OK - The voltage measurement is approximately 8 VDC 0.4 VDC. The power supply for the sensor is correct. Proceed to Test Step 2.
NOT OK - The voltage measurement is less than 8 VDC 0.4 VDC. The power supply for the sensor is not correct. Repair: If the voltage measurement is not correct, the problem is most likely in the power supply circuit. This condition will cause multiple diagnostic codes to activate.Refer to the complete Electrical System Schematic of the machine. Examine all of the connectors that are in the circuits. Ensure that the connections are clean, that all connections are secure and that all connections are in good condition.For troubleshooting the ECM power supply that is providing power to the sensor, refer to the CID 0041 diagnostic code procedures.Repair the faulty power supply circuit before proceeding with this procedure.STOPTest Step 2. CHECK FOR AN OPEN IN THE SENSOR CIRCUIT
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness connector from the pressure sensor. At the harness connector for the