BEARING 3J4728 - Caterpillar

Illustration 1 g01227464
Secondary brake solenoid connectionsThe service brake pedal switch energizes the secondary brake solenoid when the pedal closes the switch contacts. The ECM monitors this circuit for proper operation.This diagnostic code is recorded when the current of the solenoid is below normal. The secondary brake solenoid will not engage the brakes when the service brake pedal is pressed near the floor. Note: Ensure that the CID 0722 FMI 05 diagnostic code is on hold and that the fault present indicator shows "SERV CODE". In order to correctly determine the status of the fault present indicator, turn the key switch ON while the brake pedal is completely released. Completely depress the pedal and release the pedal again. The fault present indicator will only show "SERV CODE" for the CID 0722 FMI 05 diagnostic code when the pedal is released. This will happen only after the pedal has been cycled completely since the last power up. Use the same procedure in order to clear the diagnostic code after repairs have been made. Test Step 1. CHECK THE SOLENOID
Turn the key start switch to the ON position while the brake pedal is released. Press the pedal completely and then release the pedal.
Disconnect the machine harness from the secondary brake solenoid.
At the machine harness connector for the solenoid, place a jumper from contact 1 to contact 2.
Observe the status of the CID 0722 FMI 05 diagnostic code. Expected Result:The active diagnostic code changes from an FMI "05" to an FMI "06" diagnostic code as the jumper wire is installed.Results:
YES - The active diagnostic code changes from an FMI "05" to an FMI "06" diagnostic code when the jumper wire is installed. The solenoid has failed.Repair: The solenoid has failed. Repeat this Test Step "CHECK THE SOLENOID" in order to verify the solenoid failure. Replace the solenoid. Verify that the new solenoid corrects the problem.STOP
NO - The CID 0722 FMI 05 diagnostic code remains active. The jumper wire does not affect the status of the diagnostic code. The solenoid is not causing the problem. Proceed to Test Step 2.Test Step 2. CHECK THE SIGNAL CIRCUIT OF THE SOLENOID FOR AN OPEN
Turn the key start switch to the OFF position.
Disconnect the machine harness connectors J1 and J2 from the ECM.
The jumper that was used in Test Step 1 remains installed.
At machine harness connector J1, measure the resistance from J2-5 (wire G731-GY) to J2-4 (wire F761-BR) and to J1-7. Expected Result:There should be less than 5.0 ohms resistance.Results:
OK - The resistance is less than 5.0 ohms. The machine harness is correct. Proceed to Test Step 3.
NOT OK - The resistance is greater than 5.0 ohms. The resistance measurement is not correct. There is an open or a bad connection in the machine harness. A resistance measurement that is much greater than 5 ohms but less than 5000 ohms could indicate that one of the connection points in the circuit is not open but is not a good connection.Repair: The problem is in signal wire