TUBE AS 2427344 - Caterpillar

Illustration 1 g00418960
Schematic of the Solenoid Valve (Hydraulic System Main Relief)This diagnostic code is recorded when the ECM reads the voltage of the solenoid circuit as being above normal or shorted to +battery.The possible causes of this diagnostic code are listed:
The energize circuit of the solenoid is shorted to +battery.
The ECM has failed. This is unlikely. Note: Ensure that CID 0463 FMI 03 is on hold and that the diagnostic code indicator shows "SERV CODE". The nominal coil resistance at room temperature is 34.3 ohms.System Response:When this diagnostic code occurs, a warning (Category 1) is showing on the monitor. The diagnostic code will cause the solenoid to be energized at all times. The diagnostic code will maintain implement system relief at the higher pressure of the 2 preset pressures.Test Step 1. CHECK THE SOLENOID CIRCUIT FOR A SHORT TO +BATTERY.
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness from the solenoid.
Disconnect machine harness connectors from the ECM.
At the machine harness connector, measure the resistance from signal contact B-8 (wire F743-GY) to all possible sources of +battery. The possible sources of positive voltage are contact D-1 (wire 164-WH), contact D-17 (wire 850-PU), contact D-10 (wire 843-WH), contact D-11 (wire 849-YL), contact D-4 (wire 844-GN), contact B-13 (wire F793-OR), contact B-37 (wire 321-BR), contact B-8 (wire F743-GY), contact B-1 (wire 822-PK) and contact B-7 (wire 848-GY).Expected Result:Each resistance measurement should be 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 - One or more resistance measurements is not correct. There is a short in the machine harness. The short is between signal contact B-8 (wire F743-GY) and the circuit with the low resistance measurement. Repair the machine harness or replace the machine harness. Stop.Test Step 2. CHECK IF THE DIAGNOSTIC CODE REMAINS.
Inspect the contacts of the harness connectors and clean the contacts.
Reconnect all harness connectors.
Turn the disconnect switch and the key start switch to the ON position.
Enter the service mode of the Caterpillar Monitoring System and clear all of the inactive diagnostic codes.
Operate the machine.
Determine if CID 0463 FMI 03 is present. "SERV CODE" would be showing on the display.Expected Result:The diagnostic code for the solenoid is NOT present. "SERV CODE" is NOT showing on the display.Results:
YES - The diagnostic code is NOT present. The diagnostic code does not exist at this time. 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. Resume normal machine operation. Stop.
NO - The diagnostic code has not been corrected. It is unlikely that the ECM has failed.Repair: 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.