CONTROL AS-BRAKE 3511132 - Caterpillar

Illustration 1 g01228451
Thumb rocker position sensor connectionsNote: The VPAT attachment is not available on the D7R Series II machines.This diagnostic code is associated with the VPAT thumb rocker position sensor. This sensor is installed on machines that have the VPAT blade attachment installed.This diagnostic code is recorded when the ECM reads the PWM signal voltage from the position sensor wire as being above normal.Pull-up VoltageFor PWM sensor circuits, the ECM continuously outputs a "pull-up voltage" on the circuit for the sensor signal wire. When the ECM detects the presence of a voltage that is above a threshold on the signal circuit, the ECM will generate a FMI 03 diagnostic code for the involved sensor.For troubleshooting, when the sensor is disconnected from the machine harness, the presence of pull-up voltage at the sensor harness connector will indicate that the wires from the sensor connector to the ECM are OK. The absence of pull-up voltage at the sensor harness connector will indicate a possible open in the signal wire.Possible causes of the diagnostic code is listed:
The sensor power supply is open.
The signal circuit is open or the sensor is disconnected.
The signal circuit is shorted to a +battery source.
The sensor has failed.
The ECM has failed. This is unlikely. System Response:When the ECM activates diagnostic code for the position sensor, the angle functions for the blade will not operate.Note: Ensure that CID 1870 FMI 03 is active. This procedure can cause new diagnostic codes to be recorded. Ignore these created diagnostic codes. When the problem has been corrected, clear the created diagnostic codes.Test Step 1. CHECK THE SUPPLY VOLTAGE AT THE SENSOR
Turn the disconnect switch and the key start switch to the ON position.
The 12 contact connector for the sensor remains disconnected from the machine harness.
At the machine harness connector for the sensor, measure the voltage between contact 1 (wire 176-OR) and contact 2 (wire 202-BK).Expected Result:The voltage is approximately 24 VDC.Results:
OK - The voltage is approximately 24 VDC. Proceed to Test Step 2.
NOT OK - The voltage measurement is NOT 24 VDC. Repair: There may be an open in the machine harness or the implement drive train fuse may be open. Check the fuse. Ensure that the fuse is not open. If the fuse is open, replace the fuse. Clear all diagnostic codes and check to see if the diagnostic code is still active. If the code is still active, perform this step again. If supply voltage is not present at the sensor connector, there is an open in the sensor supply circuit of the machine harness. Repair the machine harness or replace the machine harness.STOPTest Step 2. CHECK FOR AN OPEN IN THE SENSOR CIRCUIT
The key start switch and the disconnect switch remain in the ON position.
Disconnect the 12 contact machine harness connector from the sensor.
At the 12 contact machine harness connector for the sensor, measure the voltage from contact 3 (wire K757-YL) to contact 2 (wire 202-BK).Expected Result:If the signal circuit and the return circuit for the position sensor are