896332135 Mercruiser HEAT EXCHANGER

Illustration 1 g00857198
SchematicTest Step 1. Check for Connector Damage
Turn the keyswitch to the OFF/RESET position.
Check the connectors and wiring for the following problems: damage, corrosion, abrasion and incorrect attachment.Expected Result:The connectors and wiring should be free of the following problems: damage, corrosion, abrasion and incorrect attachment.Results:
OK - Proceed to Test Step 2.
Not OK - Repair: Repair the connectors or wiring and/or replace the connectors or wiring.Verify that the repair eliminates the problem.STOPTest Step 2. Check the Switch Status on ET
Connect ET to the service tool connector.
Turn the keyswitch to the ON position.
Operate the ground level shutdown switch. Observe the status for the ground level shutdown switch on ET.Expected Result:The status of the switch should be "ON" with the switch in the SHUTDOWN position. The status should be "OFF" when the switch is in the RUN position.Results:
OK - The switch is operating normally.Repair: If an intermittent problem is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - Proceed to Test Step 3.Test Step 3. Short the Wires at the Switch
Disconnect the J700/P700 ground level shutdown switch.
Use a suitable piece of wire to short P700:B (Switch Return) and P700:C (Ground Level Shutdown (NC)).
Turn the keyswitch to the OFF/RESET position.
Turn the keyswitch to the ON position.
Observe the status of the ground level shutdown switch on ET.Note: The status should be "ON".
Remove the jumper wire from the connector.
Install the jumper wire between P700:B (Switch Return) and P700:A (Ground Level Shutdown (NO)).
Turn the keyswitch to the OFF/RESET position.
Turn the keyswitch to the ON position.
Observe the status of the ground level shutdown switch on ET.Note: The status should be "OFF".
Remove the jumper wire.Expected Result:The status should be "OFF" when P700:B (Switch Return) is shorted to P700:C (Ground Level Shutdown (NC)). The status should be "ON" when P700:A (Ground Level Shutdown (NO)) is shorted to P700:B (Switch Return).Results:
OK - The problem is not with the harness and/or the ECM.Repair: Temporarily connect a new switch. Verify that the new switch solves the problem before you permanently install the new switch.STOP
Not OK - There is a problem in the harness and/or the ECM. Proceed to Test Step 4.Test Step 4. Check for a Short Circuit in the Wiring Harness
Turn the keyswitch to the OFF/RESET position.
Disconnect the J1/P1 ECM connector and the J700/P700 ground level shutdown switch connector.
Measure the resistance between P1:54 (Ground Level Shutdown (NO)) and P1:18 (Switch Return).
Measure the resistance between P1:56 (Ground Level Shutdown (NC)) and P1:18 (Switch Return).
Measure the resistance between P1:54 (Ground Level Shutdown (NO)) and P1:56 (Ground Level Shutdown (NC)).
Measure the resistance between P1:56 (Ground Level Shutdown (NC)) and engine ground.
Measure the resistance between P1:54 (Ground Level Shutdown (NO)) and engine ground. Expected Result:The resistance should be greater than 20,000 Ohms for each measurement.Results:
OK - The wiring harness is not shorted. Proceed to Test Step 5.
Not OK - There is a short in the harness between the switch and the ECM.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 5. Check the Resistance through the Harness
Install a jumper wire between P700:A (Ground Level Shutdown (NO)) and P700:B (Switch Return).
Measure the resistance between P1:54 (Ground Level Shutdown (NO)) and P1:18 (Switch Return).
Remove the jumper wire.
Install the jumper wire between P700:C (Ground Level Shutdown (NC)) and P700:B (Switch Return).
Measure the resistance between P1:56 (Ground Level Shutdown (NC)) and P1:18 (Switch Return).
Remove the jumper wire.Expected Result:The resistance should be less than 10 Ohms for each measurement.Results:
OK - The resistance is within acceptable limits. Proceed to Test Step 6.
Not OK - There is an open or excessive resistance in the harness.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 6. Short the Switch Inputs at the ECM
Remove the F715-PU wire from P1:54. Remove the F716-WH wire from P1:56. Remove the J766-PU wire from P1:18. Use a 121-9587 Wire Removal Tool .
Insert a jumper wire with Deutsch sockets on each end between P1:56 and P1:18.
Reconnect all connectors.
Turn the keyswitch to the ON position.Additional diagnostic codes may be generated because the switch return will no longer be connected to the other sensors and/or switches. Clear the codes after you complete this test.
Observe the status of the ground level shutdown switch on ET.Note: The status should be "OFF".
Turn the keyswitch to the OFF/RESET position.
Disconnect the J1/P1 ECM connector.
Remove the jumper wire.
Insert the jumper wire between P1:54 and P1:18.
Reconnect all of the connectors.
Turn the keyswitch to the ON position.
Observe the status of the ground level shutdown switch on ET.Note: The status should be "ON".
Turn the keyswitch to the OFF/RESET position.
Remove the jumper wire.Expected Result:The status should be "OFF" when the wire is inserted between P1:56 and P1:18. The status should be "ON" when the wire is inserted between P1:54 and P1:18.Results:
OK - The harness is faulty.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOP
Not OK - The switch and the wiring appear to be working properly, but the ECM is not reading the switch inputs properly.Repair: Verify your results before you replace the ECM. Refer to Troubleshooting, "Replacing the ECM".STOP