IMPELLER 7L7838 - Caterpillar

Illustration 1 g02148237
Connections of the parking brake solenoid
This diagnostic code is associated with the secondary brake solenoid. The circuit is connected to an ON/OFF output of the Power Train ECM. The FMI 04 means the ECM has determined that voltage is not present in the circuit and voltage should be present.The service brake switch is depressed when the service brake pedal is fully depressed. When the switch is depressed, system voltage is directed to the secondary brake solenoid through fuse 9 and the switch contacts. Then, the secondary brake is engaged. The resistance of the solenoid coil is approximately 42 ohms at 25° C (77° F). The resistance will increase as the temperatures increase.The possible causes of this diagnostic code are listed:
The fuse is open.
The solenoid has failed.
The energize circuit of the solenoid is open between the switch and the solenoid.
The return circuit of the solenoid is open.
The switch has failed.
The ECM has failed. An ECM failure is unlikely.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 0681 - FMI 04 is active before performing 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: Use a digital multimeter for the measurements in this procedure.Test Step 1. Check the solenoid
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the J2 machine harness connector from the ECM.
At the connector for the solenoid, measure the resistance between contact "1" and contact "2". Expected Result:The resistance of the solenoid coil is approximately 42 ohms at 25° C (77° F). The resistance will increase as the temperatures increase.Results:
YES - The resistance of the solenoid coil is approximately 42 ohms at 25° C (77° F). The resistance will increase as the temperatures increase. The solenoid is correct. Proceed to Test Step 1.
NO - The resistance measurement is much greater than the expected measurement. There is a poor connection in the circuit or the solenoid is open.Repair: Disconnect the solenoid and check the resistance of the coil. Replace the solenoid if the resistance does not match the description at the beginning of this procedure. Verify that the new solenoid has corrected the problem before operating the machine.STOPTest Step 2. Check the energize circuit for an openThe key start switch and the disconnect switch remain in the OFF position. The connector remains disconnected from the solenoid.
Ensure that the parking brake switch is in the ON position.
Disconnect the J2 machine harness connector from the ECM.
At the fuse block, disconnect the blue