CAB GP 5364293 - Caterpillar

Electrical shock hazard. The electronic unit injector system uses 90-120 volts.
Turn the keyswitch to the OFF/RESET position.
Disconnect the J2/P2 ECM connector.
Measure the resistance at the P2 ECM connector between the terminals for each solenoid.Refer to Illustration 1.Expected Result:The resistance should be less than 10 Ohms.Results:
OK - Proceed to Test Step 5.
Not OK - There is an open in the harness or there is an open in the injector solenoid. Proceed to Test Step 6.Test Step 5. Check the Harness for Shorts
Disconnect the J52/P52 through J58/P58 unit injector connectors.
Measure the resistance at the P2 ECM connector between the terminals for each solenoid.Refer to Illustration 1.Expected Result:The resistance should be greater than 20,000 Ohms.Results:
OK - There are no shorts in the harness or the connectors. Proceed to Test Step 7.
Not OK - There is a short in the harness or the connectors.Repair: Repair the circuit.Verify that the repair eliminates the problem. Stop.Test Step 6. Isolate the Open Circuit
Electrical shock hazard. The electronic unit injector system uses 90-120 volts.
Turn the keyswitch to the OFF/RESET position.
Disconnect the suspect injector at the valve cover base.
Measure the solenoid resistance of the suspect injector at the valve cover base (J52 through J58). Refer to Illustration 1.Expected Result:Resistance should be less than 3.6 Ohms.Results:
OK - There is an open circuit or excessive resistance in the harness or the connectors.Repair: Repair the circuit. Refer to Troubleshooting, "Electrical Connectors - Inspect".Verify that the repair eliminates the problem. Stop.
Not OK - There is an open circuit in the valve cover base harness or the injector solenoid. Proceed to Test Step 8.Test Step 7. Measure Solenoid Resistance at Valve Cover Base
Electrical shock hazard. The electronic unit injector system uses 90-120 volts.
Turn the keyswitch to the OFF/RESET position.
Ensure that the J2/P2 ECM connector and the J52/P52 through J58/P58 unit injector connectors are disconnected.
Measure the solenoid resistance between terminals 1 and 2 and between terminals 3 and 4 at the J52 through J58 unit injector connectors. Record the measured resistance for each solenoid.Expected Result:Resistance should be between 0.6 and 3.6 Ohms for each solenoid.Results:
OK - Repair: Reconnect all connectors and repeat the Injector Solenoid Test. If the problem still exists, the ECM has a faulty injector driver. Replace the ECM. Refer to Troubleshooting, "Replacing the ECM" for the correct procedure. Stop.
Not OK - There is a problem with the valve cover base harness or the injector solenoid. Proceed to Test Step 8.Test Step 8. Check Resistance at the Injector Solenoid
Electrical shock hazard. The electronic unit injector system uses 90-120 volts.
Turn the keyswitch to the OFF/RESET position.
Remove the valve mechanism cover from the suspect cylinder.
Remove the harness yoke from the solenoid terminals.
Measure the resistance between the two solenoid terminals on top of the unit injector. Record the resistance.
Measure the resistance from either solenoid terminal to the unit injector body (metal). Record the resistance.Expected Result:Resistance between the two solenoid terminals should be between 0.6 and 3.6 Ohms.Resistance from either solenoid terminal to the fuel injector body (metal) should be greater than 20,000 Ohms.Results:
OK -