ARM & BEARING AS-LIFT 3874101 - Caterpillar

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SchematicTest Step 1. Inspect Electrical Connectors and Wiring
Turn the keyswitch to the OFF/RESET position.
Thoroughly inspect the J1/P1 ECM connector and all other connectors in the circuit. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.Expected Result:All connectors, pins, and sockets should be completely inserted and coupled. The harness and wiring should be free of corrosion, abrasion, and pinch points. All connections and grounds should be tight and free of corrosion.Results:
OK - Proceed to Test Step 2.
Not OK - Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 2. Check the Resistance through the Solenoid
Disconnect the J508/P508 fan control solenoid connector.
Measure the resistance of the sensor between J508:1 (Fan Control Solenoid) and J508:2 (Solenoid Return).Expected Result:Resistance should be between 4.5 and 5.5 Ohms.Results:
OK - Proceed to Test Step 4.
Not OK - There may be a problem with the fan control solenoid. Proceed to Test Step 3.Test Step 3. Temporarily Install a New Fan Control Solenoid
Remove the fan control solenoid.
Temporarily install a new fan control solenoid.
Turn the keyswitch to the ON position.
Clear any logged diagnostic codes.
Start the engine.
Check for diagnostic codes for the engine fan control solenoid on ET.
Ensure that the engine fan control solenoid is working properly.
Turn the keyswitch to the OFF/RESET position.Expected Result:The engine fan control solenoid should be working properly. There should be no active diagnostic codes for the engine fan control solenoid.Results:
OK - The fan control solenoid was faulty.Repair: Permanently install the new fan control solenoid.Verify that the repair eliminates the problem.STOP
Not OK - There may be a problem with the harness. Proceed to Test Step 4.Test Step 4. Check for Shorts in the Harness
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ECM connector P1
Disconnect the J1/P1 ECM connector and the J508/P508 fan control solenoid connector.
Measure the resistance between P1:43 (Fan Control Solenoid) and chassis ground.
Measure the resistance between P1:51 (Solenoid Return) and chassis ground.
Measure the resistance between P1:43 (Fan Control Solenoid) and P1:51 (Solenoid Return).Expected Result:The resistance for each measurement should be greater than 20,000 Ohms.Results:
OK - Proceed to Test Step 5.
Not OK - There is a short between the ECM and the fan control solenoid.Repair: Repair the circuit.STOPTest Step 5. Check for Open Circuits in the Harness
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ECM connector P1
Ensure that the keyswitch is in the OFF/RESET position and that the J1/P1 ECM connector is disconnected.
Use a suitable piece of wire to short P1:43 (Fan Control Solenoid) and P1:51 (Solenoid Return).
Disconnect the J508/P508 fan ontrol solenoid connector.
Measure the resistance between P508:1 (Fan Control Solenoid) and P508:2 (Solenoid Return).Expected Result:The resistance should be less than 10 Ohms.Results:
OK - Proceed to Test Step 6.
Not OK - There is an open circuit in the wiring harness between the fan control solenoid and the ECM.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 6. Measure the Current to the Fan Control Solenoid
Reconnect the J1/P1 ECM connector.
The J508/P508 fan control solenoid connector should still be disconnected. Install a jumper wire between J508:2 and P508:2.
Connect an ammeter that is capable of withstanding a 5 Amp current between J508:1 and P508:1.
Start the engine