GEAR 1276330 - Caterpillar

Electrical shock hazard. The electronic unit injector system uses 90-120 volts.
Turn the keyswitch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned off.
Disconnect the P2 ECM connector from the ECM. Connect a 257-8718 Adapter Cable As (120-PIN BREAKOUT) to the J2 ECM connector. Do not connect the engine harness to the breakout T.
Use a jumper wire to short between the socket of the suspect injector and the common socket of the suspect injector.
Turn the keyswitch to the ON position.
Perform the "Injector Solenoid Test" at least two times. Expected Result:Cat ET displays "Short" for the cylinder with the jumper wire.Note: When the engine harness is disconnected, all of the diagnostic codes for supply voltage to the sensors will be active. This is normal. Clear all of these diagnostic codes after completing this test step.Results:
OK - The ECM is OK.Repair: If two injectors that share a common wire indicate "Open", inspect the common wire for problems. The open circuit is probably caused by an open in the common wire.Repair the engine harness or replace the engine harness, as required.Verify that the repair eliminates the problem.STOP
Not OK - There may be a problem with the ECM.Repair: Temporarily connect a test ECM.Remove the breakout T and reconnect the P2 ECM connector.Perform the "Injector Solenoid Test".If the test ECM fixes the problem, reconnect the suspect ECM.If the problem returns with the suspect ECM, replace the ECM.Verify that the repair eliminates the problem.STOPTest Step 8. 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.
Turn the keyswitch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned off.
Disconnect the connectors from the valve cover base.
Turn the keyswitch to the ON position.
Perform the "Injector Solenoid Test" at least two times. Expected Result:All cylinders indicate "Open".Results:
OK - All cylinders indicate "Open". Proceed to Test Step 10.
Not OK - One or more cylinders indicate "Short". Note the cylinders that indicate "Short". Proceed to Test Step 9.Test Step 9. Check the ECM for a Short Circuit
Electrical shock hazard. The electronic unit injector system uses 90-120 volts.
Turn the keyswitch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned off.
Disconnect the P2 ECM connector from the ECM and check for evidence of moisture entry.
Turn the keyswitch to the ON position.
Perform the "Injector Solenoid Test" at least two times. Expected Result:All cylinders indicate "Open" when the P2 ECM connector is disconnected from the ECM.Note: When the engine harness is disconnected, all of the diagnostic codes for supply voltage to the sensors will be active. This is normal. Clear all of these diagnostic codes after completing this test step.Results:
OK - The short circuit is in the engine harness.Repair: The problem is most likely in the common wire to the injector. Inspect the connectors for moisture and for corrosion. Also, check the common wire