853778A 1 Mercury TOP COWL ASSEMBLY

Illustration 1 g03729651
Schematic diagram for the ECM main relay
Not all connectors are shown. Refer to the Electrical Schematic for the application.
Illustration 2 g02716384
View of the pin locations on the P1 connector for the ignition keyswitch and battery supply circuit
(1) Battery+
(2) Battery ground
(3) Battery+
(4) Battery ground
(5) Battery+
(6) Battery ground
(28) ECM main relay
(54) Ignition key switch
Table 2
Troubleshooting Test Steps Values Results
1. Inspect Electrical Connectors and Wiring
A. Check the fuses.
B. Thoroughly inspect the P1/J1 ECM connectors and thoroughly inspect the connector for the ECM main relay. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
C. Perform a 30 N (6.7 lb) pull test on each of the wires that are associated with the main relay.
Damaged wire or connector
Result: A damaged wire or damaged connector was not found. The fuses are OK.
Proceed to Test Step 2.
Result: A damaged wire or damaged connector was found. A fuse is blown.
Repair: Repair the damaged wire or the damaged connector. Replace any blown fuses.
Use the electronic service tool to clear all logged diagnostic codes. Verify that the repair eliminates the fault.
2. Check for Diagnostic Codes
A. Turn the keyswitch to the OFF position.
B. Connect the electronic service tool to the diagnostic connector.
C. Turn the keyswitch to the ON position.
D. Monitor the electronic service tool for active diagnostic codes and/or logged diagnostic codes.
Diagnostic Trouble Codes
Result: A 1485-7 diagnostic code is active or recently logged.
Proceed to Test Step 3.
Result: A 1485-14 or 2840-14 diagnostic code is active or recently logged.
Repair: Ensure that the correct procedure is used to shut down the engine. Refer to Operation and Maintenance Manual, "Stopping the Engine".
If the engine is being shut down correctly, an intermittent fault may be causing the ECM to lose battery power. Refer to Troubleshooting, "Electrical Power Supply - Test" and refer to Troubleshooting, "Electrical Connectors - Inspect".
3. Check the ECM Main Relay
A. Turn the keyswitch to the OFF position.
B. Disconnect the ECM main relay.
C. Measure the resistance between Test Point C (terminal 30) and Test Point D (terminal 87) on the relay.
Open circuit
Result: The resistance measurement indicates "Open Circuit"
Proceed to Test Step 4.
Result: The resistance measurement indicates continuity between Test Point C and Test Point D on the relay.
Repair: Replace the ECM main relay.
Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.
4. Check the Wiring Between the Relay and the ECM
A. Turn the keyswitch to the OFF position.
B. Disconnect the ECM main relay. Disconnect the P1 connector.
C. Measure the voltage between Test Point A (terminal 86) and Test Point B (terminal 85) on the harness connector for the ECM main relay.
0 V
Result: The voltage measurement is 0 VDC.
Contact the Dealer Solution Network (DSN).
Result: The voltage measurement indicates battery voltage.
The wiring between Test Point B on the harness connector for the relay and P1:28 is shorted to ground.
Repair: Check all wiring between the ECM main relay and the P1 connector. Refer to the Electrical Schematic for the application.
Replace the faulty wiring.
Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.
If the procedure did not correct the issue, contact the Dealer Solution Network (DSN).