76566 Mercury SCREW, (#10-24 x 1.00)

Illustration 1 g01260600
Schematic for the digital sensor supply
Illustration 2 g01267106
Cooling fan drive assembly
(1) Cooling fan drive assembly
(2) Connector for the engine fan speed sensor
Illustration 3 g01193730
Mounting location of the throttle position sensor on the throttle pedal (typical example)
Test Step 1. Inspect the Electrical Connectors and the Wiring
Remove electrical power from the ECM.
Illustration 4 g01270661
ECM connectors (typical example)
(3) J1/P1 ECM connector
Thoroughly inspect all connectors. Inspect the connectors for each digital sensor. Refer to Troubleshooting, "Electrical Connectors - Inspect".
Illustration 5 g01260697
P1 ECM connector
(P1-5) Sensor return
(P1-4) +8 V digital supply
(P1-32) Engine fan speed
(P1-66) Throttle position
Illustration 6 g01159881
Sensor connector
(Terminal A) +8 V supply
(Terminal B) Sensor return
(Terminal C) Sensor signal
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the digital sensor supply.
Check the allen head screw on the ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and wiring for abrasions and for pinch points from the battery to the ECM. Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted, and the harness and wiring are free of corrosion, of abrasion, and of pinch points.Results:
OK - The connectors and wiring are OK. Proceed to Test Step 2.
Not OK - There is a problem 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. Check for Active Diagnostic Codes
Connect the Caterpillar Electronic Technician (ET) to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools".
Restore electrical power to the ECM.
Monitor the active diagnostic code screen on Cat ET. Check for an active 41-03 code and an active 41-04 code. Note: Wait at least 30 seconds in order for the diagnostic codes to become active.
Remove electrical power from the ECM. Expected Result:No diagnostic codes are active.Results:
OK - No diagnostic codes are active.Repair: If any of the above codes are logged and the engine is not running properly, refer to Troubleshooting, "Troubleshooting Without a Diagnostic Code".If the engine is running properly at this time, there may be an intermittent problem in a harness that is causing the codes to be logged. Refer to Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - Either the 41-03 or 41-04 diagnostic code is active at this time. Proceed to Test Step 3.Test Step 3. Disconnect the Digital Sensors and Check for Active Diagnostic Codes
Restore electrical power to the ECM.
Monitor the active diagnostic code screen on Cat ET while you disconnect each digital sensor connector. Check for an active 41-03 code or an active 41-04 code. Note: Wait at least 30 seconds in order for the diagnostic codes to become active.
Disconnect the following sensors one at a time:
Throttle position sensor
Engine fan speed sensorExpected Result:The diagnostic code deactivates when a particular sensor is disconnected.Results:
OK - The 41-03 or 41-04 diagnostic code deactivates when a particular sensor is disconnected.Repair: Connect the suspect sensor. If the code returns, replace the sensor. The fan speed sensor is nonserviceable. The fan speed sensor is integral to the fan drive assembly. Replace the fan drive assembly. Connect all of the connectors. Verify that the problem is resolved.STOP
Not OK - The 41-03 or 41-04 diagnostic code remains active after all of the sensors are disconnected. The sensors are not the cause of the diagnostic code. Leave the sensors disconnected. Proceed to Test Step 4.Test Step 4. Check the Supply Voltage at the ECM
Remove electrical power from the ECM.
Disconnect the J1/P1 ECM connectors.
Disconnect the J2/P2 ECM connectors.
Fabricate two jumper wires that are long enough to be used as test leads at the ECM connectors. Crimp connector sockets to one end of each jumper wire.
Remove the wires from terminal locations P1-4 (8 V sensor supply) and P1-5 (sensor return). Install a jumper wire into each of these terminal locations.
Connect the J1/P1 and J2/P2 ECM connectors.
Restore electrical power to the ECM.
Measure the voltage between the jumper wire in P1-4 (8 V sensor supply) and P1-5 (sensor return).
Remove electrical power from the ECM. Expected Result:The voltage measurement is 8.0 0.4 VDC at the ECM connector.Results:
OK - The voltage measurement is 8.0 0.4 VDC at the ECM connectors.Repair: The ECM is operating correctly. The supply wires are shorted to another wire in the harness or the supply wires are shorted to engine ground. Repair the wiring and/or the connector. Replace parts, if necessary. Verify that the problem is resolved.