5034033 JOHNSON UNIT, ENGINE CONTROL - 90HP

Illustration 1 g00687331
Schematic for 8 cylinder engines
Illustration 2 g00712248
Schematic for 12 cylinder engines
Illustration 3 g00893821
8 cylinder P2 ECM connector (5) Solenoid 1/3 Return (16) Solenoid 1 Power (17) Solenoid 2/4 Return (26) Solenoid 2 Power (27) Solenoid 5/7 Return (30) Solenoid 7 Power (31) Solenoid 6 Power (32) Solenoid 3 Power (36) Solenoid 8 Power (37) Solenoid 5 Power (38) Solenoid 4 Power (39) Solenoid 6/8 Return
Illustration 4 g00893822
12 cylinder P2 ECM connector (5) Solenoid 1/3 Return (11) Solenoid 2/4 Return (12) Solenoid 12 Power (16) Solenoid 1 Power (17) Solenoid 5/7 Return (18) Solenoid 10 Power (21) Solenoid 6/8 Return (22) Solenoid 8 Power (26) Solenoid 3 Power (27) Solenoid 9/11 Return (28) Solenoid 6 Power (31) Solenoid 11 Power (32) Solenoid 5 Power (33) Solenoid 10/12 Return (34) Solenoid 4 Power (37) Solenoid 9 Power (38) Solenoid 7 Power (40) Solenoid 2 PowerTest Step 1. Inspect Electrical Connectors And Wiring
Electrical shock hazard. The electronic unit injector system uses 90-120 volts.
Turn the keyswitch to the OFF/RESET position. A strong electrical shock hazard is present if the ignition key is not turned OFF.
Thoroughly inspect the J2/P2 ECM connector and the J52/P52 through J58/P58 unit injector connectors. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Check the harness and wiring for abrasion and for pinch points from the injectors to the ECM.Expected Result:All connectors, pins, and sockets are completely inserted and coupled. The harness and wiring are free of corrosion, of abrasion, and of pinch points.Results:
OK - Proceed to Test Step 2.
Not OK - Repair: Repair the circuit. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.Verify that the repair eliminates the problem.STOPTest Step 2. Check for Logged Diagnostic Codes
Connect the Caterpillar Electronic Technician (ET) to the service tool connector.
Turn the keyswitch to the ON position.
Observe the diagnostic codes on Cat ET.Expected Result:The following diagnostic codes are not logged:
1-05 Injector Cylinder 1 open circuit through
12-05 Injector Cylinder 12 open circuit
1-06 Injector Cylinder 1 short through
12-06 Injector Cylinder 12 shortResults:
OK - None of the diagnostic codes are logged. Proceed to Test Step 3.
Not OK - One or more of the diagnostic codes are logged. Proceed to Test Step 4.Test Step 3. Perform the Injector Solenoid Test
Turn the keyswitch to the ON position.
Perform the Injector Solenoid Test on Cat ET.
As each solenoid is energized by the ECM an audible click can be heard at the valve mechanism cover. Listen for a click at each valve mechanism cover.Note: Repeat the Injector Solenoid Test a few times in order to verify that the ECM is energizing each solenoid.Expected Result:As each solenoid is energized by the ECM, an audible click of the solenoid is heard.Results:
OK - All of the solenoids were energized. Proceed to Test Step 9.
Not OK - One or more solenoids were not energized. Proceed to Test Step 4.Test Step 4. Check the Harness Resistance
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 3 for 8 cylinder engines. Refer to Illustration 4 for 12 cylinder engines.Expected Result:The resistance is 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 3 for 8 cylinder engines. Refer to Illustration 4 for 12 cylinder engines.Expected Result:The resistance is 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.STOPTest 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).Expected Result:Resistance is less than 3.6 Ohms.Results:
OK - There is an open circuit or excessive resistance in the harness or the connectors.