CONT GP 2705435 - Caterpillar

Illustration 1 g01353729
Connections of the service brake pedal position sensor
This diagnostic code is recorded when the ECM determines that the signal for the service brake pedal position sensor has an abnormal pulse width, abnormal frequency, or an abnormal period. The service brake pedal position sensor is a PWM sensor. The signal wire for the service brake pedal position sensor connects to connector contact J2-27 (wire F774-PU(Purple)) of the ECM.The possible causes for this diagnostic code are listed:
The circuit for the +battery to the sensor has a intermittent connection.
The return circuit from the sensor has a intermittent connection.
The signal circuit from the sensor has a intermittent connection.
The sensor has failed.Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear these diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of CID 0468 FMI 08 is active before performing this procedure.Use a digital multimeter for the measurements in the procedure.System Response:A level 2 warning will be generated. The Action lamp will be ON and flashing.Test Step 1. CHECK THE SENSOR.
Observe the ON/OFF status of the diagnostic code indicator.
Disconnect the harness from the sensor. Expected Result:The diagnostic code indicator is active.Results:
YES - The diagnostic code indicator is active. This indicates that the diagnostic code remains active. The sensor is not causing the diagnostic code. Proceed to test step 2.
NO - The diagnostic code indicator is inactive. The diagnostic code is inactive.Repair: The sensor has failed. Replace the sensor.STOPTest Step 2. CHECK THE HARNESS.
The sensor remains disconnected from the harness.
Turn the disconnect switch to the OFF position.
Disconnect the harness from the ECM.
At the harness connector for the sensor, measure the resistance between signal contact C (wire F774-WH(White)) and ground. Expected Result:The resistance is greater than 5000 Ohms.Results:
YES - The resistance is greater than 5000 Ohms.Repair: The harness circuit resistance is correct. It is unlikely that an ECM has failed. Exit this procedure. Perform this troubleshooting procedure again. If the diagnostic code is not found, replace the ECM. See Troubleshooting, "Electronic Control Module (ECM) - Replace".STOP
NO - The resistance is less than 5000 Ohms. The harness has failed.Repair: There is a short between frame ground and the signal circuit in the harness. Repair the harness or replace the harness.STOPTest Step 3. CHECK THE OUTPUT OF THE SENSOR.
Reconnect the machine harness connectors to the ECM. Reconnect the machine harness connector to the sensor.
At the harness connector for the sensor, connect the positive lead from the multimeter to contact C.
At the harness connector for the sensor, connect the negative lead from the multimeter to contact B.
Turn the disconnect switch and the key start switch to the ON position.
Set the multimeter to the setting for frequency (Hz). Measure the output of the sensor. Expected Result:The PWM