879355T81 Mercruiser ECM, Engine Control Module

Illustration 1 g01839594
Typical schematic for the starting aid switch
Illustration 2 g01805855
View of the pin locations on the P1 connector for the starting aid circuit
(1) Ground (GND)
(2) Ground (GND)
(3) Ground (GND)
(9) Ground (GND)
(10) Ground (GND)
(57) Start aid control
(63) Cold start lamp Test Step 1. Inspect Electrical Connectors and Wiring
Inspect the following connectors:
P1 connector
P2 connector
Inspect the terminal connections on the glow plug start aid relay. 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 glow plug starting aid.
Check the screw for the ECM connector for the correct torque of 5.0 N m (44 lb in).
Check the harness for abrasion and pinch points from the glow plugs back to the ECM.
Check that the fuses are not blown. Expected Result:All connectors, pins and sockets are correctly coupled and/or inserted. The harness is free of corrosion, abrasion and pinch points. The fuses are not blown.Results:
OK - The harness and the connectors appear to be OK. Proceed to Test Step 2.
Not OK - There is a fault with the harness and connectors.Repair: Repair the connectors or the harness and/or replace the connectors or the harness. Ensure that all of the seals are correctly in place and ensure that the connectors are completely coupled. Replace blown fuses.Use the electronic service tool in order to clear all logged diagnostic codes and then verify that the repair has eliminated the fault.STOPTest Step 2. Check for Active Diagnostic Codes
Connect the electronic service tool to the diagnostic connector.
Turn the keyswitch to the ON position. Note: Do not start the engine.
Use the electronic service tool to select the "Glow Plug Start Aid Override Test" in order to turn on the power for the glow plugs.
Check for active diagnostic codes or recently logged diagnostic codes. Expected Result:The following diagnostic code is active or recently logged:
2246-06 Glow Plug Start Aid Relay Current Above NormalResults:
OK - The expected diagnostic code is active or recently logged. Proceed to Test step 3.
Not OK - An active diagnostic code or a recently logged diagnostic code was not displayed.Repair: Perform one of the following procedures:
If an intermittent fault is suspected, use the electronic service tool to perform a "Wiggle Test" in order to locate intermittent connections.
If there is a fault on the glow plug or a fault on the starting aid and a diagnostic code is not displayed then there may be a fault with the glow plug switched power circuit or there may be an open circuit in the relay coil circuit. The ECM does not monitor the status of these tests. Refer to Testing and Adjusting, "Glow Plugs - Test".STOPTest Step 3. Check the Wiring for a Short Circuit
Turn the keyswitch to the OFF position.
Remove the P1 connector from the ECM.
Check the connector, pins and the sockets for corrosion or damage.
Check the resistance between P1:57 and each of the pins on the P1 connector. Expected Result:The resistance between P1:57 and P1:63 is approximately 2,000 Ohms.The resistance between P1:57 and each of the remaining pins on the P1 connector is more than 10,000 Ohms.Results:
OK - The harness connects the ECM to the glow plug start aid relay and there are no shorts to other circuits. The ECM or the glow plug start aid relay is suspect. Proceed to Test Step 4.
Not OK - The harness is faulty.Repair: If the resistance between P1:57 and P1:63 is less than 2,000 Ohms then there is a short circuit or high resistance in the connection to another wire. If the resistance between P1:57 and each of the remaining pins on the J1 connector is less than 10,000 Ohms then there is a short circuit or high resistance in the connection to another wire. Locate the open circuit, the short circuit or high resistance in the connection in the harness. Repair the connectors or the harness and/or replace the connectors or the harness. Ensure that all of the seals are correctly in place and ensure that the connectors are correctly coupled. Replace any fuses that may be open circuit.Use the electronic service tool in order to clear all logged diagnostic codes and then verify that the repair has eliminated the fault.If the fault still exists,