HOUSING-MOTOR 2003489 - Caterpillar

Illustration 1 g01226169
Service brake pedal position sensor connections
Illustration 2 g01226423
Location of the service brake position sensorThis diagnostic code is recorded when the ECM reads the service brake position sensor signal as being above normal. The possible causes of this diagnostic code are listed:
The sensor power supply is open.
The return circuit (wire 202-BK) is open.
The signal circuit is open or the sensor is disconnected.
The signal circuit is shorted to the + 24 volt sensor power supply.
The sensor has failed.
The ECM has failed. This is unlikely. Note: Ensure that CID 0468 FMI 03 is on hold.Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when problem has been corrected.System Response:The diagnostic code will cause the pedal to stop functioning. The diagnostic code will not affect any other machine operations.Test Step 1. CHECK THE VOLTAGE AT THE SENSOR
Turn the disconnect switch and the key start switch to the ON position.
Disconnect the sensor from the machine harness.
At the machine harness connector for the sensor, measure the voltage between contact A (wire 176-OR) and contact B (wire 202-BK).Expected Result:The voltage is approximately 23 DCV.Results:
OK - The voltage is approximately 23 DCV. Proceed to Test Step 3.
NOT OK - The voltage measurement is NOT 23 DCV. 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, proceed to Test Step 2.Test Step 2. CHECK FOR AN OPEN IN THE SUPPLY CIRCUIT
The key start switch and the disconnect switch remain in the ON position.
The sensor remains disconnected from the machine harness.
At the machine harness connector for the sensor, measure the voltage from contact A (wire 176-OR) to frame ground.Expected Result:The voltage measurement should be approximately 23 DCV.Results:
OK - The voltage measurement is approximately 23 DCV.Repair: There may be an open in the return circuit. Wire 202-BK is open between the sensor and the ECM. Repair the machine harness or replace the machine harness.STOP
NOT OK - The voltage measurement is less than 23 DCV.Repair: The supply circuit is not correct. Proceed to Test Step 3.Test Step 3. CHECK FOR AN OPEN IN THE SIGNAL CIRCUIT
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the J1 and J2 machine harness connector from the ECM.
At the machine harness connector for the sensor, install a jumper wire from contact C (wire F790-BR) to contact B (wire 202-BK).
At the machine harness connector J1 and J2, measure the resistance from contact J2-32 (wire F790-BR) to contact J1-13 (wire 202-BK).Expected Result:The resistance should measure less than 5 ohms.Results:
OK - The resistance measures less than 5 ohms. Proceed to 4.
NOT OK - The resistance measurement is greater than 5 ohms.Repair: There is an open or a bad connection in the signal circuit.