SEAL 1950601 - Caterpillar

Turn the keyswitch to the OFF position. A strong electrical shock hazard is present if the ignition key is not turned OFF.
Remove the valve cover.
Disconnect the harness from the problem injector at the connector that is attached to the injector solenoid. For example, if the number one injector is the suspect injector, disconnect P301 from J301.
Turn the keyswitch to the ON position.
Access the "Injector Solenoid Test" on Cat ET and perform the test three times.Note: Ensure that the seal is installed in the harness connector before connecting the harness to the connector. If the seal is missing, use a replacement seal. Ensure that the seal is not stuck in the injector connector.Expected Result:The status for the injector that is disconnected changes to "OPEN" when the harness is disconnected.Results:
OK - The wiring up to the injectors appears to be OK.Repair: Temporarily connect a new injector to the harness. Run the "Injector Solenoid Test". If all cylinders indicate "OK", turn the keyswitch to OFF and reconnect the old injector. If the original injector again reads "OPEN", replace the injector. Restore the wiring to the proper injectors. Use the "Injector Solenoid Test " to verify that the repair eliminates the problem.Do not install the valve cover until the problem is resolved. Clear all diagnostic codes.STOP
Not OK - There is a short in the wiring harness under the valve cover.Repair: Replace the injector wiring harness under the valve cover.Verify that the repair eliminates the problem.STOPTest Step 8. Check for Short Circuits between the ECM and the J300/P300 Injector Harness Connector
Electrical shock hazard. The electronic