864398T 1 Mercruiser HOUSING ASSEMBLY, Thermostat, Thermostat

Illustration 1 g01055096
Typical schematic
Illustration 2 g01091329
P1 ECM connector
(P1-8) Cat Data Link +
(P1-9) Cat Data Link − Test Step 1. Inspect Electrical Connectors and Wiring
Turn the Engine Control Switch (ECS) to the OFF/RESET position.
Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect all of the other connectors that are associated with the circuit. 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 that are associated with the circuit.
Check the ECM connectors (allen head screw) for the proper torque of 6 N m (55 lb in).
Check the harness and the wiring for abrasion and for pinch points. Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted, and the harness and wiring are free of corrosion, of abrasion or of pinch points.Results:
OK - The connectors and wiring are okay. Proceed to Test Step 2.
Not OK - The connectors and/or wiring need repair.Repair: Repair the connectors and/or wiring or replace the connectors and/or wiring.Repair CompleteTest Step 2. Check for Shorts in the Harness
Disconnect the P1 ECM connector from the ECM.
Disconnect any module that is connected to the Cat Data Link.
Measure the resistance from the following terminals to every terminal on ECM connector P1. Measure the resistance from the following terminals to engine ground. Wiggle the harness during the measurements in order to reveal an intermittent short.
P1-8 (Cat Data Link +)
P1-9 (Cat Data Link −)Expected Result:The resistance is more than 20,000 Ohms for each measurement.Results:
OK - The resistance is greater than 20,000 Ohms. Proceed to Test Step 3.
Not OK - The resistance is less than 20,000 Ohms. There is a short in the harness or in the connectors.Repair: Repair the connector and/or wiring or replace the connector and/or wiring.Repair CompleteTest Step 3. Check for an Open in the Harness
Disconnect the ECM connectors for the ECM.
Disconnect any module that is connected to the Cat Data Link.
Short the wires of the Cat Data Link together. Create the short at P1-9 and P1-8 of the ECM connector.
Set an ohmmeter on the 200 Ohm scale. Measure the resistance between the terminals of the Cat Data Link + and the Cat Data Link −. Measure the resistance between the terminals of any module that was connected to the Cat Data Link. Wiggle the harness during the measurements in order to reveal an intermittent open condition.
Reconnect all connectors and modules. Expected Result:The resistance is less than 5 Ohms for each measurement.Results:
OK - The resistance is less than 5 Ohms for each measurement.Repair: The harness is okay. There could be a problem with a module or with the ECM. Connect the suspect module to another engine. If the problem returns on the other engine, replace the suspect module. Turn the ECS to the OFF/RESET position. Turn the ECS to the STOP position. If the diagnostic code is still present, replace the ECM. Refer to Troubleshooting, "Replacing the ECM".STOP
Not OK - The resistance is greater than 5 Ohms for each measurement.Repair: There is an open circuit or there is excessive resistance in the harness. Repair the connectors and/or wiring or replace the connectors and/or wiring.Repair Complete