SPOOL-PRESSURE RELIEF 7N5449 - Caterpillar

Conditions Which Generate This Code:This diagnostic code is recorded when the second output driver in the MSS ECM is shorted to ground. This circuit is not used on all machines. Check for the presence of wires at contact 5 and contact 52 before you perform the procedure.The possible causes of this diagnostic code are listed below:
The wiring in the machine harness has failed.
The driven component in the circuit has failed.
The ECM has failed. This is unlikely.Test Step 1. CHECK THE WIRING HARNESS.
Disconnect the wiring harness connector from the MSS ECM.
Measure the resistance between pin 18 in the wiring harness and a ground on the machine.Expected Result:The resistance is greater than 5000 Ohms.Results:
YES - The resistance is greater than 5000 Ohms (no continuity). Harness circuit resistance is correct. Proceed to Test Step 3.
NO - Resistance is less than 5000 Ohms (continuity). The machine harness is faulty. There is a short between frame ground and the machine harness. The driven component in the circuit may also be bad. Proceed to Test Step 2.Test Step 2. CHECK THE COMPONENT.
Trace the harness to the driven component in the circuit. The component will be a relay. The component may also be a solenoid.
Measure the resistance of the component. Measure the resistance from each terminal to the case of the component.Expected Result:The resistance is greater than 5000 Ohms.Results:
YES - The resistance of the driven component is greater than 5000 Ohms (no continuity). The component is good. The machine harness has failed. There is a short between frame ground and the machine harness.Repair: Check the harness for signs of damage. Repair the machine harness or replace the machine harness. Stop.
NO - Resistance is less than 5000 Ohms (continuity). The driven component has failed. Repair: Replace the component that has failed. Stop.Test Step 3. CHECK IF THE DIAGNOSTIC CODE IS STILL ACTIVE.
Remove the connector from the ECM. Inspect the contacts and clean the contacts of the harness connectors.
Reconnect all harness connectors.
Turn the key start switch to the ON position.
Clear all inactive diagnostic codes.
Operate the machine.
Determine if CID 1392 FMI 04 is present.Expected Result:CID 1392 FMI 04 is present.Results:
YES - CID 1392 FMI 04 is present.Repair: The problem has not been corrected. It is unlikely that the ECM has failed. Perform the previous Steps 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 - CID 1392 FMI 04 is not present.Repair: The diagnostic code is NOT present. The problem does not exist at this time. The initial problem was probably caused by an intermittent short in the wiring harness. Inspect the harness for any signs of damage. If the harness passes through a hole with a grommet, that area of the harness can become chafed. This may cause an intermittent short. The harness may also be damaged in locations that could pinch the harness. Repair any wiring that could have caused the problem. Resume normal machine operation. Stop.