CARRIER 0005220 - Caterpillar

The Electronic Control Module (ECM) controls the speed of the fan by controlling the current to the fan control solenoid. The fan control solenoid controls the displacement of the hydraulic pump that supplies pressurized oil to the fan motor. The fan control solenoid is controlled by a signal between 0.3 and 1.6 amp. The fan pump defaults to maximum pressure and a diagnostic code is generated if no signal is sent to the solenoid.
Illustration 1 g01013762
Schematic
Illustration 2 g01007882
P1 ECM connector
Test Step 1. Inspect Electrical Connectors and Wiring
Place the engine control in the OFF/RESET mode.
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 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 connectors and the wiring appear to be OK. Proceed to Test Step 2.
Not OK - There is a problem with the connectors and/or the wiring.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 solenoid between J508:4 (Fan Control Solenoid) and J508:3 (Solenoid Return). Expected Result:The resistance is between 4.5 and 5.5 Ohms.Results:
OK - The resistance is between 4.5 and 5.5 Ohms. 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.
Connect the Caterpillar Electronic Technician (ET) to the service tool connector.
Place the engine control in the ON mode.
Clear any logged diagnostic codes on Cat ET.
Start the engine.
Check for diagnostic codes for the engine fan control solenoid on Cat ET.
Ensure that the engine fan control solenoid is working properly.
Place the engine control in the OFF/RESET mode. Expected Result:The engine fan control solenoid is working properly and there are 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
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 is greater than 20,000 Ohms.Results:
OK - The resistance for each measurement is greater than 20,000 Ohms. Proceed to Test Step 5.
Not OK - There is a short in the harness between the ECM and the fan control solenoid.Repair: Repair the circuit.STOPTest Step 5. Check for Open Circuits in the Harness
Place the engine control in the OFF/RESET mode. Ensure that the J1/P1