C7.1 Engines and Generator Sets Caterpillar

Cooling Fan Reversing - Test - Hydraulic Driven Fan

Usage:

C7.1 770

This procedure is only applicable to engines with a hydraulic driven fan.

Use this procedure to troubleshoot any suspected faults with the engine fan reverse switch or the fan reversing solenoid.

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Table 1
Diagnostic Trouble Codes for Cooling Fan Reversing
J1939 Code	CDL Code	Code Description	Comments
4214-5	485-5	Engine Fan Reverse Actuator : Current Below Normal	This code indicates that there is an open circuit in the engine reversing fan solenoid circuit.
4214-6	485-6	Engine Fan Reverse Actuator : Current Above Normal	This code indicates that there is a short circuit in the engine reversing fan solenoid circuit.

The purpose of a reversing fan is to clean debris from the radiator. Cleaning is achieved by temporarily reversing the direction of the air flow through the radiator fins to purge the radiator fins.

In the automatic mode, the fan reversing solenoid is controlled by the engine Electronic Control Module (ECM). The ECM will automatically reverse the direction of the fan rotation. The ECM will use a preset time interval to cycle the fan reversing solenoid.

The operator can manually reverse the fan rotation by pressing the engine fan reverse switch. While the momentary switch is depressed, the direction of the fan rotation will reverse. Once the switch is allowed to reset, the fan returns to normal operation and control of the fan will return to the automatic operation.

During the following procedure, refer to the electrical schematic for the application.

Complete the procedure in the order in which the steps are listed.

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Table 2
Troubleshooting Test Steps	Values	Results
1. Determine the Diagnostic Code A. Establish communication between the electronic service tool and the engine Electronic Control Module (ECM). Refer to Troubleshooting, "Electronic Service Tools", if necessary. B. Download the "Warranty Report" from the engine ECM before performing any troubleshooting or clearing diagnostic trouble codes. C. Look for active or logged codes.	Active Codes	Result: An active or logged 4214-5 (485-5) code is present. Proceed to Test Step 2. Result: An active or logged 4214-6 (485-6) code is present. Proceed to Test Step 3.
2. Check for an Open Circuit A. Turn the keyswitch to the OFF position. B. Disconnect the engine reversing fan solenoid connector from the wiring harness. C. Verify that the harness connector is free of debris, free of corrosion, and is securely connected. D. Connect a jumper wire between the terminals of the harness connector for the engine reversing fan solenoid. The solenoid coil is replaced with a short circuit. E. Turn the keyswitch to the ON position F. Use the "Engine Reversing Fan Solenoid Override" in the electronic service tool to turn the solenoid ON. G. Check for active codes.	Short Circuit	Result: A 4214-5 (485-5) code became active. An open circuit has been detected in the wiring harness. Repair: Repair the wiring or replace the wiring. Proceed to Test Step 4. Result: A 4214-6 (485-6) code became active. The short circuit was detected by the ECM. Repair: Install a replacement engine reversing fan solenoid. Proceed to Test Step 4.
3. Check for a Short Circuit A. Turn the keyswitch to the OFF position. B. Disconnect the engine reversing fan solenoid connector from the wiring harness. C. Verify that the harness connector is free of debris, free of corrosion, and is securely connected. D. Turn the keyswitch to the ON position E. Check for active codes.	Open Circuit	Result: A 4214-5 (485-5) code became active. The open circuit was detected by the ECM. Repair: Install a replacement engine reversing fan solenoid. Proceed to Test Step 4. Result: A 4214-6 (485-6) code became active. A short circuit has been detected. Repair: Repair the wiring or replace the wiring. Proceed to Test Step 4.
4. Check the Engine Reversing Fan Operation A. Start the engine. B. Activate the engine reversing fan using the engine reversing fan switch.	Switch	Result: The engine reversing fan is not operating correctly. Proceed to Test Step 5. Result: The engine reversing fan is operating correctly. Return the unit to service.
5. Check the Engine Reversing Fan Switch A. Disconnect the engine reversing fan solenoid connector from the wiring harness. B. Use a jumper wire to short circuit the signal and ground wires together on the harness side of the connector for the switch. C. Turn the keyswitch to the ON position D. Connect to the electronic service tool. Monitor the engine reversing fan switch parameters in the status screen. E. Wait at least 30 seconds and check the status of the engine fan reverse switch on the electronic service tool. The correct status for the switch is ONwhile the jumper wire is in place. F. Remove the jumper wire from the connector. Wait at least 30 seconds and check the status of the engine fan reverse switch on the electronic service tool. The correct status for the switch is OFF with the jumper wire removed.	Status Change	Result: The switch status changed in the electronic service tool. A failed engine reversing fan switch has been detected. Repair: Install a replacement engine reversing fan switch. Verify that the fault has been resolved. Return the unit to service. Result: The switch did not change status in the electronic service tool. A wiring fault between the switch and the ECM has been detected. Repair: Repair or replace the wiring harness between the switch and the engine harness. Verify that the fault has been resolved. Return the unit to service. If the fault is still present, contact the Dealer Solutions Network (DSN).