MANIFOLD GP-CONTROL 4561838 - Caterpillar

Electrical shock hazard. The electronic unit injector system uses 90-120 volts.
Place the engine control in the OFF/RESET mode. A strong electrical shock hazard is present if the engine control is not placed in the OFF/RESET mode.
Remove the valve cover.
Disconnect the harness from the problem injector. Disconnect the harness from the other injector that has the same injector common line.
Thoroughly clean the terminals of both injectors and of the harness.
Exchange the harness between the two injectors that share the common line.
Place the engine control in the ON mode.
Perform the injector solenoid test at least two times. Expected Result:Exchanging the harness between the two injectors caused the problem to move to the other injector on Cat ET.Results:
OK - Cat ET indicates that the problem has moved.Repair: Replace the faulty injector. Restore the wiring to the proper injectors.Verify that the repair eliminates the problem.STOP
Not OK - Cat ET still indicates that the problem is with the original injector.Repair: Replace the injector harness under the valve cover.Verify that the repair eliminates the problem.STOPTest Step 10. Check the Engine Harness Under the Valve Cover for an Open Circuit in the Common Line
Illustration 5 g00706832
Harness terminals of electronic unit injector
Electrical shock hazard. The electronic unit injector system uses 90-120 volts.
Place the engine control in the OFF/RESET mode. A strong electrical shock hazard is present if the engine control is not placed in the OFF/RESET mode.
Remove the valve cover.
Disconnect each of the injectors that indicate an "OPEN" from the wiring harness. Ensure that each of the connectors from the disconnected injector harness does not touch other components and short to ground.
Attach a jumper wire to both terminals of the injector harness for the two injectors that share an injector common line.
Place the engine control in the ON mode.
Perform the injector solenoid test at least two times. Expected Result:The cylinders with the short in place indicate an "OPEN".Results:
OK - The problem appears to be in the engine harness under the valve cover.Repair: Perform the following repair:
Replace the engine harness under the valve cover.
Run the injector solenoid test in order to check the installation of the new harness before installing the valve covers.
Verify that the repair eliminates the problem. STOP
Not OK - Both injectors indicate "SHORT".Repair: Replace both injectors.Verify that the repair eliminates the problem.STOPTest Step 11. Check the Engine Harness Under the Valve Cover for Short Circuits in the Injector Wires
Electrical shock hazard. The electronic unit injector system uses 90-120 volts.
Place the engine control in the OFF/RESET mode. A strong electrical shock hazard is present if the engine control is not placed in the OFF/RESET mode.
Remove the valve cover.
Disconnect each of the injectors that indicate a "SHORT" from the wiring harness. Ensure that each of the connectors from the disconnected injector harness does not touch other components and short to ground.
Place the engine control in the ON mode.
Perform the injector solenoid test at least two times. Expected Result:Both cylinders indicate an "OPEN".Results:
OK - Neither of the injector wires are shorted to the engine.Repair: Leave the injector wires