PISTON 3556558 - Caterpillar

Illustration 1 g01735233
Schematic for the "Brake Cooling Pump" solenoid
This diagnostic code is associated with the brake cooling pump solenoid. The FMI 03 means that the ECM has determined that the voltage of the solenoid circuit is above normal.Some possible causes of the diagnostic code are listed below:
The solenoid has failed.
The energize circuit of the solenoid is shorted to the +battery circuit.
The ECM has failed. This is unlikely.System Response:When the CID 1230 FMI 03 diagnostic code is active, the machine response can be:
The ECM will not control the differential cooling fan.
The differential cooling fan may run at maximum speed when the key start switch is ON.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 1230 FMI 03 is active before performing this procedure.Test Step 1. CHECK THE ENERGIZE CIRCUIT OF THE SOLENOID FOR A SHORT TO THE +BATTERY CIRCUIT
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness connector from the solenoid. Disconnect the machine harness connectors J-1 and J-2 from the Brake ECM.
At the machine harness connector of the Brake ECM J1, measure the resistance from contact J1-49 (wire J817-WH(White)) to all J-1 and J-2 contacts that are connected to the +battery. Expected Result:Each resistance measurement is greater than 5000 ohms. Results:
OK - Each resistance measurement is greater than 5000 ohms. The machine harness is correct. Proceed to Test Step 2.
NOT OK - Each resistance measurement is not greater than 5000 ohms. There is a short in the machine harness. The short is between J1-49 (wire J817-WH(White)) and the circuit that has a low resistance measurement. Repair: Repair the machine harness or replace the machine harness.STOPTest Step 2. CHECK IF THE DIAGNOSTIC CODE IS STILL ACTIVE
Inspect the contacts of the harness connectors that are used in the solenoid circuit. Ensure that the contacts are secure. Clean all of the contacts in the harness connectors.
Reconnect all harness connectors.
Turn the disconnect switch and the key start switch to the ON position.
Operate the machine.
Determine if the CID 1230 FMI 03 diagnostic code is active. Expected Result:The CID 1230 FMI 03 diagnostic code is active.Results:
YES - The CID 1230 FMI 03 diagnostic code is active.Repair: Repeat this procedure. If the problem remains, replace the solenoid. After the solenoid is replaced, repeat this Test Step again. If the diagnostic code is still active, the ECM may be faulty. It is unlikely that the ECM has failed. Exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found, replace the ECM. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace".STOP
NO - The CID 1230 FMI 03 diagnostic code is not active. The problem does not exist at this time.Repair: The initial diagnostic code was probably caused by a poor electrical connection or a short at one of the harness connectors that was disconnected and reconnected.