5004471 JOHNSON REPAIR KIT, Mixing unit

Illustration 1 g01222824
Schematic
Test Step 1. Inspect Electrical Connectors and Wiring
Remove the electrical power from the ECM.
Thoroughly inspect the J1/P1 Electronic Control Module (ECM) connector and all other connectors in the wiring harness. Refer to diagnostic functional tests Troubleshooting, "Electrical Connectors - Inspect".
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector and the sensor connectors that are associated with the active diagnostic code.
Check the ECM connector (allen head screw) for the proper torque. Refer to diagnostic functional tests Troubleshooting, "Electrical Connectors - Inspect". 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. All connections and grounds are tight and free of corrosion.Results:
OK - The harness and wiring are OK. Proceed to Test Step 2.
Not OK - There is a problem with the harness and/or wiring.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 2. Check the Resistance through the Solenoid
Remove the electrical power from the ECM.
Disconnect the push/pull solenoid for the variable pitch fan.
Measure the resistance between 1 (Push Solenoid) and 2 (Digital Return).
Measure the resistance between 4 (Pull Solenoid) and 3 (Digital Return). Expected Result:Resistance is 25 5 Ohms.Results:
OK - The push/pull solenoid for the variable pitch fan has the correct resistance. Proceed to Test Step 3.
Not OK - The resistance is not acceptable. The push/pull solenoid for the variable pitch fan is faulty.Repair: Install a new push/pull solenoid for the variable pitch fan.Verify that the repair eliminates the problem.STOPTest Step 3. Check the Status of the Manual Purge Switch
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Restore the electrical power to the ECM.
Observe the status for "Engine Fan Manual Purge Switch" on Cat ET while you operate the switch.
Remove the electrical power from the ECM. Expected Result:The status of the switch is "On" when the switch is depressed. The status reads "Off" when the switch is released.Results:
OK - The status shows the expected result. The manual purge switch is working properly. Proceed to Test Step 5.
Not OK - The status does not show the expected result. The ECM does not recognize the input from the manual purge switch. Proceed to Test Step 4.Test Step 4. Check the Manual Purge Switch
Remove the electrical power from the ECM.
Disconnect the manual purge switch connector.
Measure the continuity between A (Manual Purge Switch) and B (Digital Return) with the manual purge switch in the released position.
Measure the continuity between A (Manual Purge Switch) and B (Digital Return) with the manual purge switch in the depressed position. Expected Result:There is no continuity between A (Manual Purge Switch) and B (Digital Return) when the switch is in the released position. There is continuity between A (Manual Purge Switch) and B (Digital Return) when the switch is in the depressed position.Results:
OK - There is no continuity when the switch is in the released position. There is continuity when the switch is in the depressed position. Proceed to Test Step 5.
Not OK - The continuity of the circuit is not acceptable. There is a problem with the manual purge switch.Repair: Replace the manual purge switch with a new switch.Verify that the repair eliminates the problem.STOPTest Step 5. Check for Shorts in the Harness for the Variable Pitch Fan
Illustration 2 g01223077
P1 ECM connector
(P1-18) Digital return
(P1-19) Push solenoid
(P1-20) Pull solenoid
(P1-45) Manual purge switch
(P1-65) −Battery
Disconnect the J1/P1 ECM connector.
Measure the resistance between P1-45 (Manual Purge Switch) and chassis ground.
Measure the resistance between P1-20 (Pull Solenoid) and chassis ground.
Measure the resistance between P1-19 (Push Solenoid) and chassis ground.
Measure the resistance between P1-45 (Manual Purge Switch) and P1-18 (Digital Return).
Measure the resistance between P1-20 (Pull Solenoid) and P1-18 (Digital Return).
Measure the resistance between P1-19 (Push Solenoid) and P1-18 (Digital Return).
Measure the resistance between P1-45 (Manual Purge Switch) and P1-20 (Pull Solenoid).
Measure the resistance between P1-45 (Manual Purge Switch) and P1-19 (Push Solenoid).
Measure the resistance between P1-20 (Pull Solenoid) and P1-19 (Push Solenoid). Expected Result:The resistance for each measurement does not indicate short.Results:
OK - The resistance is acceptable. There are no shorts in the harness. Proceed to Test Step 6.
Not OK - The resistance is not acceptable. There is a short between the ECM and the push/pull solenoid and/or the manual purge switch.Repair: Repair the circuit.STOPTest Step 6. Check for Open Circuits in the Harness for the Variable Pitch Fan
Remove the electrical power from the ECM and disconnect the J1/P1 ECM connector.
Use a suitable piece of wire to short P1-45 (Manual Purge Switch) and P1-18 (Digital Return).
Disconnect the push/pull solenoid connector.
Disconnect the manual purge switch connector.
Measure the resistance between B (Manual Purge Switch) and C (Digital Return).
Use a suitable piece of wire to short P1-20 (Pull Solenoid) and P1-18 (Digital Return).
Measure the resistance between 4 (Pull Solenoid) and 3 (Digital Return).
Use a suitable piece of wire to short P1-19 (Push Solenoid) and P1-18 (Digital Return).
Measure the resistance between 1 (Push Solenoid) and 2 (Digital Return).
Remove all shorts and reconnect all connectors. Expected Result:The resistance does not indicate an open circuit.Results:
OK - The resistance is acceptable. The wiring harness for the variable pitch fan is operating correctly. The ECM is not sending the correct signal to the push/pull solenoid for the variable pitch fan.Repair: Verify your results. Replace the ECM. Refer to electronic troubleshooting Troubleshooting, "Replacing the ECM".Verify that the repair eliminates the problem.STOP
Not OK - The resistance is not acceptable. There is an open circuit between the ECM and the push/pull solenoid and/or the manual purge switch.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOP