AFTERCOOLER GP-AIR 2067335 - Caterpillar

Use this procedure to troubleshoot any suspect problems with the fan control solenoid for the engine cooling fan.This procedure covers the 291-12 Engine Cooling Fan Solenoid malfunction.The Electronic Control Module (ECM) controls the speed of the fan by regulating the control current to the fan control solenoid. A Pulse Width Modulated signal (PWM) is generated by the ECM. This signal is used by the solenoid to control an oil bypass valve for the variable speed fan clutch.The ECM utilizes information from the engine coolant temperature sensor and from the inlet air temperature sensor in order to determine the fan speed that is required for the current operating conditions.The control current from the ECM is used by the solenoid in order to regulate the amount of oil that is allowed to bypass the fan clutch. At "100% Bypass", the ECM will send a maximum duty cycle to the solenoid and the fan speed will be at the minimum. At "0% Bypass", the ECM sends a minimum duty cycle to the solenoid and the fan speed will be at the maximum.The ECM controls the rpm of the engine fan in order to provide the following benefits:
Increased productivity
Reduced noise
Improved fuel economy
Reduced overcooling of the engine
Illustration 1 g01184669
Schematic for the engine cooling fan solenoid
Test Step 1. Inspect the Electrical Connectors and the Wiring
Turn the keyswitch to the OFF position.
Illustration 2 g01146374
Left side engine view (typical example)
(1) J1/P1 ECM connector
Illustration 3 g01183942
Engine cooling fan assembly (typical example)
(2) Engine cooling fan speed sensor connector
(3) Cooling fan drive assembly
Thoroughly inspect connectors (1). Also, thoroughly inspect connector (2) that is for the integral components of fan drive (3). Refer to Troubleshooting, "Inspecting Electrical Connectors" for details.
Illustration 4 g01184650
P1 terminal locations for the engine fan control solenoid
(P1-11) Engine fan control solenoid
(P1-69) Solenoid return
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.
Check the allen head screw for each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and the wiring for abrasion and for pinch points.Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted. The harness and wiring are free of corrosion, of abrasion, and of pinch points.Results:
OK - The harness and wiring appear to be OK. Proceed to Test Step 2.
Not OK - A problem has been found in the connectors and/or wiring.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled. Verify that the repair eliminates the problem.STOPTest Step 2. Use Caterpillar Electronic Technician (ET) to check the Actual Speed of the Fan
Turn the keyswitch to the OFF position.
Connect Cat ET to the service tool connector.
Turn the keyswitch to the ON position. Establish communications with the engine ECM.
Access the "Fan Override Test" under the "Diagnostics" menu.
Start the "Fan Override Test" on Cat ET. Set the fan speed to the following speeds:
Minimum allowable speed
Maximum