879172028 Mercruiser COVER ASSEMBLY, Front

Illustration 1 g00761072
SchematicTest Step 1. Inspect Electrical Connectors and Wiring
Turn the keyswitch to the OFF/RESET position.
Thoroughly inspect the J1/P1 ECM connector, the J3/P3 machine connector, and all other connectors in the wiring harness. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector and the sensor connectors that are associated with the active diagnostic code.
Check the ECM connector (allen head screw) for the proper torque of 6.0 N m (55 lb in).
Inspect the following components for damage, corrosion, and incorrect attachment:
Battery posts
Alternator
Breaker
Engine ground
Chassis groundExpected Result:All connectors, pins, and sockets are inserted and coupled. The harness and wiring are free of corrosion, of abrasion, and of pinch points. All connections and grounds are tight and free of corrosion.Results:
OK - The harness and wiring are OK. Proceed to Test Step 2.
Not OK - There is a problem with the harness and/or wiring.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 2. Check the Starting Aid Switch Status on the Electronic Service Tool
Remove the ether canister from the ether solenoid.
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Turn the keyswitch to the ON position.
Press the starting aid switch to "MANUAL". Observe the "Starting Aid Switch Status" on Cat ET.Expected Result:When the starting aid switch is pressed, Cat ET should display the status of the starting aid switch as ON.When the starting aid switch is not pressed, Cat ET should display the status of the starting aid switch as OFF.Results:
OK - Cat ET displayed the expected results. The starting aid switch is operating correctly. Proceed to Test Step 6.
Not OK - Cat ET did not display the expected results. The ECM is not properly reading the signal from the starting aid switch. Proceed to Test Step 3.Test Step 3. Check the Resistance of the Relay
Illustration 2 g00761074
Connector for the ether relay
Turn the keyswitch to the OFF/RESET position.
Disconnect the wires at terminal 86 (Ether ON) and terminal 85 (Solenoid Return) at the ether relay.
Measure the resistance across terminal 86 (Ether ON) and terminal 85 (Solenoid Return).
Reconnect the wires to the ether relay.Expected Result:The resistance is between 250 Ohms and 500 Ohms.Results:
OK - The resistance is acceptable. Proceed to Test Step 4.
Not OK - The resistance is not acceptable. The relay is faulty.Repair: Replace the relay.Verify that the repair eliminates the problem.STOPTest Step 4. Short the Switch Wires
Remove wire F721-GY (Starting Aid Switch) and wire 998-BR (Digital Return) from the starting aid switch.
Short wire F721-GY (Starting Aid Switch) to wire 998-BR (Digital Return).Expected Result:When the wires are shorted, Cat ET displays the status of the starting aid switch as ON.When the wires are not shorted, Cat ET displays the status of the starting aid switch as OFF.Results:
OK - Cat ET displayed the expected results. The starting aid switch is not operating correctly.Repair: Replace the starting aid switch.Verify that the repair eliminates the problem.STOP
Not OK - Cat ET did not display the expected results. Proceed to Test Step 5.Test Step 5. Short the Switch Inputs at the ECM
Illustration 3 g00936533
J1/P1 breakout
Turn the keyswitch to the OFF/RESET position and install a 7X-1715 Adapter Cable (40 Pin Breakout T) at the J1/P1 ECM connector.
Turn the keyswitch to the ON position.
Use a suitable piece of wire to short P1:19 (Starting Aid Switch) and P1:29 (Digital Return) at the breakout.
Observe the results on the "Status" screen on Cat ET.Expected Result:When the wires are shorted, Cat ET displays the status of the starting aid switch as ON.When the wires are not shorted, Cat ET displays the status of the starting aid switch as OFF.Results:
OK - Cat ET displayed the expected results. There is a problem in the wiring between the switch and the ECM.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOP
Not OK - Cat ET did not display the expected results. The ECM is not reading the switch input properly.Repair: Verify your results. Replace the ECM. Refer to Troubleshooting, "Replacing the ECM" before replacing the ECM.Verify that the repair eliminates the problem.STOPTest Step 6. Check the Resistance of the Ether Solenoid
Turn the keyswitch to the OFF/RESET position.
Disconnect the J37/P37 ether solenoid connector.
Measure the resistance between J37:1 (Solenoid Power) and J37:2 (Solenoid Return).Expected Result:The resistance is less than ten Ohms.Results:
OK - Resistance is less than ten Ohms. Proceed to Test Step 7.
Not OK - Resistance is more than ten Ohms. The ether solenoid is faulty.Repair: Replace the ether solenoid.Verify that the repair eliminates the problem.STOPTest Step 7. Check the Supply Voltage to the Ether SolenoidNote: The ether canister must be removed prior to activating this test.
Turn the keyswitch to the ON position.
Proceed to the "Diagnostic Override Screen" on C