863121 Mercruiser STUD, (M8 x 194)

Illustration 1 g01625557
Schematic diagram for the throttle switches (31 pin MIC)
Illustration 2 g01625558
Schematic diagram for the throttle switches (70 pin MIC)
Illustration 3 g01625559
Pin locations on the ECM connector
(11) Throttle Switch No.3
(19) Throttle Switch No.4
(20) Throttle Switch No.2
(28) Throttle Switch No.1
(37) Switch Return
Illustration 4 g01625560
Pin locations on the 31 pin MIC
(21) Throttle Switch No.1
(22) Throttle Switch No.4
(24) Throttle Switch No.3
(25) Throttle Switch No.2
(28) Switch Return
Illustration 5 g01332051
Pin locations on the 70 pin MIC
(11) Throttle Switch No.3
(19) Throttle Switch No.4
(20) Throttle Switch No.2
(28) Throttle Switch No.1
(37) Switch Return
Illustration 6 g01332048Test Step 1. Inspect Electrical Connectors and Wiring
Turn the keyswitch to the OFF position.
Thoroughly inspect ECM connector J1/P1, machine interface connector J20/P20, and the battery connections. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Check the harness and wiring for corrosion, abrasion, and pinch points from the throttle switch to the ECM. Expected Result:All connectors, pins, and sockets should be completely inserted and coupled. The harness and wiring should be free of corrosion, abrasion, and pinch points.Results:
OK - Proceed to Test Step 2.
Not OK - Repair: Repair the circuit.Verify that the repair eliminates the fault.STOPTest Step 2. Check "Throttle Switch Position" on the Electronic Service Tool
Turn the keyswitch to the OFF position.
Connect the electronic service tool to the diagnostic connector.
Turn the keyswitch to the ON position.
Observe the status of the throttle switch and the throttle inputs on the electronic service tool while you operate the throttle switch in each position. Expected Result:The status on the electronic service tool should correspond with the information that is displayed on the "Throttle Configuration Screen" on the electronic service tool. For an example, refer to Illustration6.Results:
OK - The throttle switch is functioning correctly.Repair: Refer to Troubleshooting, "Electrical Connectors - Inspect" if the fault is intermittent.STOP
Not OK - Record the suspect input. Proceed to Test Step 3.Test Step 3. Jumper the Switch Input at the Suspect Throttle Position Switch
Turn the keyswitch to the OFF position.
Observe the status of the suspect throttle input on the electronic service tool.
On applications with a 31 pin MIC, use a suitable jumper wire to short P20:28 Switch Return to the terminal for the suspect throttle input on the P20 connector.
On applications with a 70 pin MIC, use a suitable jumper wire to short P20:37 Switch Return to the terminal for the suspect throttle input on the P20 connector.
Observe the status of the suspect throttle input on the electronic service tool.
Remove the wire short. Expected Result:The status of the suspect throttle input should be "OFF" when the jumper wire is disconnected. The status should be "ON" when the jumper wire is connected.Results:
OK - The engine harness and the ECM are OK.Repair: Repair the machine wiring or replace the machine wiring or the suspect throttle switch. Refer to the documentation for the application.Verify that the repair eliminates the fault.STOP
Not OK - Proceed to Test Step 4.Test Step 4. Check for Shorts in the Harness
Turn the keyswitch to the OFF position.
Disconnect the J1/P1 ECM connector.
Disconnect the J20/P20 MIC connector.
On applications with a 31 pin MIC, measure the resistance between the following pairs of pins:
P1:11 and P20:24 Throttle Switch No.3
P1:19 and P20:22 Throttle Switch No.4
P1:20 and P20:25 Throttle Switch No.2
P1:28 and P20:21 Throttle Switch No.1
P1:37 and P20:28 Switch Return
On applications with a 70 pin MIC, measure the resistance between the following pairs of pins:
P1:11 and P20:11 Throttle Switch No.3
P1:19 and P20:19 Throttle Switch No.4
P1:20 and P20:20 Throttle Switch No.2
P1:28 and P20:28 Throttle Switch No.1
P1:37 and P20:37 Switch ReturnExpected Result:The measured resistance should be less than 10 ohms.Results:
OK - Proceed to Test Step 5.
Not OK - There is a fault in a wire between the P1 connector and the P20 connector.Repair: Repair the circuit.Verify that the repair eliminates the fault.STOPTest Step 5. Test the Engine ECM
Turn the keyswitch to the OFF position.
Insert a 70 pin Breakout T between the P1 connector and J1 connector.
Insert one end of a jumper wire into the socket for the suspect switch. Insert the other end of the jumper wire into P1:37 switch return.
Turn the keyswitch to the ON position and monitor the status screen on the electronic service tool. Slowly connect and disconnect the jumper wire from the socket of pin 37 of the Breakout T. Expected Result:The status screen should display an OPEN condition with the switch in the OFF position.The status screen should display a CLOSED condition with the switch in the ON position.Results:
OK - The ECM is working correctly.STOP
Not OK - Th