INJECTOR GP- 7C9580 - Caterpillar

Test Step 1. CHECK THE ENABLE CIRCUITS FOR AN OPEN
Turn the key start switch and the battery disconnect switch to the OFF position.
At the EFR, disconnect the 14 contact control circuit harness connector from the module connector. Visually inspect each of the connector contacts for damage or contamination. Verify that the contacts are clean, secured in the connector, and in good condition.
At the control circuit harness connector for the EFR, connect a jumper wire between the enable circuit contact J (wire E865) and the return circuit contact M (wire E866).
At the Drivetrain ECM, disconnect the J1 and the J2 harness connectors. Visually inspect each of the connector contacts for damage or contamination. Verify that the contacts are clean, secured in the connector, and in good condition.
At the harness connectors J1 and J2, use a multimeter to check the resistance between the enable circuit contact J1-12 (wire E865) and the return circuit contact J2-4 (wire E866).
While observing the resistance measurement, wiggle the harness connectors for the Drivetrain ECM. If possible, have someone wiggle the harness connector at the EFR. Do not disconnect the jumper wire. Expected Result:The resistance measurement is less than 5.0 ohms at all times during the manipulation of the wiring harnesses.Results:
OK - The resistance measurement is less than 5.0 ohms at all times. The resistance measurement is not indicating that there is an open or a poor connection in the enable circuit or the return circuit. Proceed to Test Step 2.
NOT OK - The resistance measurement is greater than 5.0 ohms. There is a problem in one or both of the enable circuits.Repair: The round 24 contact MC-C3 / EF-C1 connectors that pass the circuits through the cab wall are a good point to disconnect and check the cab harness. The contacts for these connectors are illustrated in the connection diagram at the beginning of this procedure.With the jumper wire connected, disconnect the cab wall connector and check the resistance of the circuits back toward the EFR harness connector. This check will help to determine whether the problem is in the cab harness or in the chassis harness.In the harness where the suspect problem is located, check the end to end continuity in each section of the enable circuit and the return circuit between each harness connector. Check the pins and sockets in each connector for damage or contamination. Ensure that all connections are clean, secure, and in good condition.Refer to the complete machine Electrical System Schematic. Identify and locate the connectors that are used in the circuits between the ECM and the EFR. Repair the machine harness or replace the machine harness. STOPTest Step 2. CHECK THE OPERATION OF THE ECMNote: This check is intended to determine is the ECM is responding correctly to a change in the circuit. The battery disconnect switch and the key start switch remain in the OFF position.
Reconnect the 14 contact control circuit harness connector to the EFR module.
At the machine harness connector J2 for the Drivetrain ECM, use a