SPOOL-VALVE 1178905 - Caterpillar

diagnostics for the electronic control module (ECM) can be accessed through one of the following tools:
Cat® Electronic Technician (Cat® ET) service tool
The operator monitorWhen the troubleshooting procedure says “REPAIR THE HARNESS OR REPLACE THE HARNESS”, use the machine Electrical Schematic to trace the circuit. Perform continuity checks at the harness connectors to locate harness failures. At the connectors of the components, always check the ground circuit. Less than 5 ohms of resistance is required between the ground contacts of the connector and the frame ground. The power circuits of the ECM should have less than 2 ohms of resistance between the contacts of the ground connector and the frame ground. Less than 5 ohms of resistance is required for signal circuits for normal operation. Ground resistance greater than 5 ohms can cause incorrect diagnosing of problems.Inspect all connections before any component is replaced. Connections that are not clean and tight can result in permanent or intermittent electrical problems can result. Check that the wires are pushed into the connectors completely. Make sure that the connections are tight before other tests are made.Failure of an electrical component can cause the failure of other components. Failure of an electrical component can be caused by the failure of other components. Always attempt to correct the cause of an electrical failure before replacing a component.