SENSOR 2390844 - Caterpillar

Electrical shock hazard. The electronic unit injector system uses 90-120 volts.
Remove the electrical power from the ECM.
Disconnect the J300/P300 injector valve cover entry connector at the valve cover base.
Restore the electrical power to the ECM.
Fabricate a jumper wire that will be long enough to short circuit the different terminal locations at the P300 connector. Crimp connector pins on both ends of the jumper wire.
Insert one end of the jumper wire into the P300 connector socket for the suspect injector's supply wire. Insert the other end of the jumper wire into the P300 connector socket for the suspect injector's return wire. This will replace the injector solenoid with a short circuit.
Perform the "Injector Solenoid Test" at least two times.
Repeat this test for each suspect circuit. Stop the "Injector Solenoid Test" before handling the jumper wire. Restore the wiring to the original configuration.Expected Result:Cat ET displays "Short" for each of the circuits that were jumpered.Results:
OK - Cat ET displays "Short" for each circuit that was jumpered. The harness between the ECM and the P300 connector does not have an open circuit. Proceed to Test Step 6.
Not OK - Cat ET displays "Open" for the cylinder with the jumper wire. There is a problem in the wiring between the ECM and the P300 connector. Proceed to Test Step 7.Test Step 6. Check the Harness between the ECM and the Valve Cover Base for a Short Circuit
Electrical shock hazard. The electronic unit injector system uses 90-120 volts.
Remove the electrical power from the ECM.
Disconnect the P300 connector.
Restore the electrical power to the ECM.
Perform the "Injector Solenoid Test" at least two times.Expected Result:All of the cylinders indicate "Open" on Cat ET.Results:
OK - All cylinders indicate "Open" on Cat ET. Proceed to Test Step 7.
Not OK - One or more cylinders indicate "Short" on Cat ET. Note the cylinders that indicate "Short". Proceed to Test Step 8.Test Step 7. Check the Injector Harness Under the Valve Cover for an Open Circuit or a Short Circuit
Electrical shock hazard. The electronic unit injector system uses 90-120 volts.
Remove the electrical power from the ECM.
Remove the valve cover in order to gain access to the suspect injector.
Disconnect the harness connector from the suspect injector.
Thoroughly clean the terminals on the injector solenoid and on the harness connector.
Use a jumper wire to short circuit the connector terminals for the suspect injector. This will effectively replace the injector solenoid with a short circuit.
Restore the electrical power to the ECM.
Perform the "Injector Solenoid Test" at least two times.Note: The injector solenoid that shares the supply wire of the injector that is short circuited may indicate a false test result. Disregard this test result.
Remove the electrical power from the ECM.
Remove the jumper wire from the injector connector. This will effectively replace the injector solenoid with an open circuit.
Restore the electrical power to the ECM.
Perform the "Injector Solenoid Test" at least two times.
Remove the electrical power from the ECM.Expected Result:Cat ET displays "Short" for the cylinder with the jumper wire and "Open" when the jumper