F1905 Force FILL HD SCREW, 1/4 - 20 X 3 7/16

Table 1
Diagnostic Codes Table
CDL Code Code Description Comments
291-5 Engine Cooling Fan Solenoid : Current Below Normal The Electronic Control Module (ECM) detects an open circuit in the circuit for the engine fan control solenoid.
The ECM sends minimum current to the fan control solenoid. The code is logged.
291-6 Engine Cooling Fan Solenoid : Current Above Normal The ECM detects a short circuit to ground in the circuit for the engine fan control solenoid.
The ECM sends minimum current to the fan control solenoid. The code is logged. The ECM monitors engine coolant temperature, intake manifold air temperature, and hydraulic oil temperature. The correct speed for the "Engine Cooling Fan" is then determined.The ECM controls the speed of the fan by controlling the current to the "Engine Fan Control" solenoid. The "Engine Fan Control" solenoid controls the amount of pressure to the fan pump by allowing oil to bypass the fan pump. The fan pump drives the fan. The ECM outputs minimum current to the "Engine Fan Control" solenoid to bypass less oil. The fan pump will then drive the fan at a higher rpm. The ECM outputs maximum current to the "Engine Fan Control" solenoid to bypass more oil. The fan pump will then drive the fan at a lower rpm.Note: The control valve oil lines come off the cylinder block supply port. Therefore, the oil pressure to the valve should be equal to the engine oil pressure when the solenoid is closed. (No oil is flowing to the fan clutch). The outlet should be equal to the crankcase pressure, and within 34 kPa (5 psi) of the engine oil pressure in and out, when open. (Oil is flowing to the fan clutch).If the ECM detects a system fault, the ECM provides minimum current to the solenoid. The fan speed will be at maximum while the fault condition exists.An override is available with Cat® Electronic Technician (Cat® ET). The fan can then be manually changed from the minimum to the maximum rpm.
Illustration 1 g02061556
Schematic for the engine fan control solenoid
Table 2
Troubleshooting Test Steps Values Results
1. Check for Active Diagnostic Codes
A. Turn the key switch to the OFF position.
B. Verify that the solenoid connector is free of debris and connected securely.
C. Connect Cat® ET to the service tool connector.
D. Turn the key switch to the ON position.
E. Select diagnostic tests from Cat® ET.
F. Select the "Override Parameters" screen on Cat® ET
G. Activate the fan override.
H. Monitor the active diagnostic code screen on Cat® ET. Check and record any active diagnostic codes.
Note: Wait at least 30 seconds in order for the diagnostic code to become active.
I. Disable the fan override.
Codes Result: No diagnostic codes are active.
Repair: The problem may have been related to a faulty connection in the harness. Carefully inspect the connectors and wiring. Refer to Troubleshooting, "Electrical Connectors - Inspect".
STOP
Result: A short circuit diagnostic code -6 is active currently.
Proceed to Test Step 2.
Result: An open circuit diagnostic code -5 is active currently.
Proceed to Test Step 3.
2. Disconnect the Connector for the Engine Fan Control Solenoid to Create an Open Circuit
A. Turn the key switch to the OFF position.
B. Disconnect the connector for the engine fan control solenoid.
C. Turn the key switch to the ON position.
D. Activate the fan override.
E. Monitor the active diagnostic code screen on Cat® ET. Check and record any active diagnostic codes.
Note: Wait at least 30 seconds in order for the diagnostic code to become active.
F. Disable the fan override.
Short Circuit Result: A short circuit diagnostic code -6 remains active. There is a short circuit between the harness connector for the engine fan control solenoid and the ECM.
Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Clear any logged diagnostic codes. Verify that the problem is resolved.
STOP
Result: A short circuit diagnostic code -6 was active before disconnecting the connector. An open circuit diagnostic code -5 became active after disconnecting the connector.
Repair: Replace the engine fan control solenoid. Clear any logged diagnostic codes. Verify that the problem is resolved.
STOP
3. Create a Short at the Connector for the Engine Fan Control Solenoid
A. Turn the key switch to theOFF position.
B. Fabricate a jumper wire that is long enough to create a short between the terminals of the connector for the engine fan control solenoid. Crimp connector pins to each end of the jumper wire.
C. Install the jumper wire between "Terminal 1" (engine fan control solenoid) and "Terminal 2" (solenoid return) on the harness side of the connector
D. Turn the key switch to theON position.
E. Activate the fan override.
F. Monitor the active diagnostic code screen on Cat® ET. Check and record any active diagnostic codes.
Note: Wait at least 30 seconds for the diagnostic code to become active.
G. Disable the fan override. Remove the jumper wire.
Open Circuit Result: The open circuit diagnostic code -5 remains active with the jumper in place.
Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Clear any logged diagnostic codes. Verify that the problem is resolved.
STOP
Result: A short circuit diagnostic code -6 is active when the jumper wire is installed. An open circuit diagnostic code -5 is active when the jumper wire is removed.
Repair: Replace the engine fan control solenoid. Clear any logged diagnostic codes. Verify that the problem is resolved.
STOP
Test Step 1. The procedure corrected the issue. Return to service.Results:
The procedure did not correct the issue. - Repair: Contact your Cat® dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).STOP