0311232 JOHNSON COVER,Flywheel

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Schematic
Test Step 1. INSPECT ELECTRICAL CONNECTORS AND WIRING
Turn the keyswitch to the OFF position.
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Thoroughly inspect the J1/P1 ECM connector and all other connectors in the wiring harness. Refer to Troubleshooting, "Electrical Connectors - Inspect".
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P1 ECM connector
(P1-3) Return
(P1-5) Return
(P1-12) Reversing solenoid
(P1-46) Manual purge switch
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 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
Turn the keyswitch to the OFF position.
Disconnect the reversing solenoid for the variable pitch fan.
Measure the resistance between 1 (Solenoid) and 2 (Return). Expected Result:Resistance is 32 5 Ohms.Results:
OK - The reversing solenoid for the variable pitch fan has the correct resistance. Proceed to Test Step 3.
Not OK - The resistance is not acceptable. The reversing solenoid for the variable pitch fan is faulty.Repair: Install a new reversing 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.
Turn the keyswitch to the ON position.
Observe the status for "Engine Fan Manual Purge Switch" on Cat ET while you operate the switch.
Turn the keyswitch to the OFF position. 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
Turn the keyswitch to the OFF position.
Disconnect the manual purge switch connector.
Measure the continuity between 46 (Manual Purge Switch) and 3 (Return) with the manual purge switch in the released position.
Measure the continuity between 46 (Manual Purge Switch) and 3 (Return) with the manual purge switch in the depressed position. Expected Result:There is no continuity between 46 (Manual Purge Switch) and 3 (Return) when the switch is in the released position. There is continuity between 46 (Manual Purge Switch) and 3 (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 FAN
Disconnect the J1/P1 ECM connector.
Measure the resistance between P1-46 (Manual Purge Switch) and chassis ground.
Measure the resistance between P1-12 (Reversing Solenoid) and chassis ground.
Measure the resistance between P1-46 (Manual Purge Switch) and P1-5 (Return).
Measure the resistance between P1-12 (Reversing Solenoid) and P1-3 (Return).
Measure the resistance between P1-46 (Manual Purge Switch) and P1-12 (Reversing 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 reversing solenoid and/or the manual purge switch.Repair: Repair the circuit.STOPTest Step 6. CHECK FOR OPEN CIRCUITS IN THE HARNESS FOR THE FAN
Remove the electrical power from the ECM and disconnect the J1/P1 ECM connector.
Use a suitable piece of wire to short P1-46 (Manual Purge Switch) and P1-3 (Return).
Disconnect the reversing solenoid connector.
Disconnect the manual purge switch connector.
While the switch is activated, measure the resistance between 46 (Manual Purge Switch) and 3 (Return).
Use a suitable piece of wire to short P1-12 (Reversing Solenoid) and P1-5 (Return).
Measure the resistance between 12 (Reversing Solenoid) and 5 (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 fan is operating correctly. The ECM is not sending the correct signal to the reversing solenoid for the fan.Repair: Verify your results. Replace the ECM. Refer to Troubleshooting, "ECM - Replace".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 reversing solenoid and/or the manual purge switch.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOP