0345103 JOHNSON CAM, Accelerator pump

Illustration 1 g00761418
SchematicTest Step 1. Inspect Electrical Connectors and Wiring
Turn the keyswitch to the OFF/RESET position.
Thoroughly inspect the J1/P1 Electronic Control Module (ECM) connector, the J3/P3 machine connector, and all other connectors in the wiring harness. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
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 of 6.0 N m (55 lb in).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. Stop.Test Step 2. Check the Resistance through the Solenoid
Verify that the keyswitch is in the OFF/RESET position.
Disconnect the push/pull solenoid for the variable pitch fan.
Measure the resistance between J160:1 (Push Solenoid) and J160:2 (Digital Return).
Measure the resistance between J160:4 (Pull Solenoid) and J160:3 (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. Stop.Test 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/RESET 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/RESET position.
Disconnect the J161/P161 manual purge switch connector.
Measure the continuity between P161:A (Manual Purge Switch) and P161:B (Digital Return) with the manual purge switch in the released position.
Measure the continuity between P161:A (Manual Purge Switch) and P161:B (Digital Return) with the manual purge switch in the depressed position.Expected Result:There is no continuity between P161:A (Manual Purge Switch) and P161:B (Digital Return) when the switch is in the released position. There is continuity between P161:A (Manual Purge Switch) and P161: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. Stop.Test Step 5. Check for Shorts in the Harness for the Variable Pitch Fan
Illustration 2 g00936850
P1 ECM connector
Disconnect the J1/P1 ECM connector.
Disconnect the J160/P160 push/pull solenoid connector.
Disconnect the J161/P161 manual purge switch connector.
Measure the resistance between P1:15 (Manual Purge Switch) and chassis ground.
Measure the resistance between P1:28 (Pull Solenoid) and chassis ground.
Measure the resistance between P1:34 (Push Solenoid) and chassis ground.
Measure the resistance between P1:15 (Manual Purge Switch) and P1:29 (Digital Return).
Measure the resistance between P1:28 (Pull Solenoid) and P1:29 (Digital Return).
Measure the resistance between P1:34 (Push Solenoid) and P1:29 (Digital Return).
Measure the resistance between P1:15 (Manual Purge Switch) and P1:28 (Pull Solenoid).
Measure the resistance between P1:15 (Manual Purge Switch) and P1:34 (Push Solenoid).
Measure the resistance between P1:28 (Pull Solenoid) and P1:34 (Push Solenoid).Expected Result:The resistance for each measurement is greater than 20,000 Ohms.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. Stop.Test Step 6. Check for Open Circuits in the Harness for the Variable Pitch Fan
Illustration 3 g00936850
J1/P1 breakout
Verify that the keyswitch is in the OFF/RESET position and disconnect the J1/P1 ECM connector.
Use a suitable piece of wire to short P1:15 (Manual Purge Switch) and P1:29 (Digital Return).
Disconnect the J160/P160 push/pull solenoid connector.
Disconnect the J161/P161 manual purge switch connector.
Measure the resistance between J161:B (Manual Purge Switch) and J161:C (Digital Return).
Use a suitable piece of wire to short P1:28 (Pull Solenoid) and P1:29 (Digital Return).
Measure the resistance between P160:4 (Pull Solenoid) and P160:3 (Digital Return).
Use a suitable piece of wire to short P1:34 (Push Solenoid) and P1:29 (Digital Return).
Measure the resistance between P160:1 (Push Solenoid) and P160:2 (Digital Return).
Remove all shorts and reconnect all connectors.Expected Result:The resistance is less than 10 Ohms.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 Troubleshooting, "Replacing the ECM" before 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.