862148T 3 Mercruiser ECM, Engine Control Module

Illustration 1 g01264891
C15 schematic
Illustration 2 g01261068
C11 schematic
Illustration 3 g01261336
P1 ECM connections
(P1-48) +Battery
(P1-52) +Battery
(P1-63) −Battery
(P1-61) −Battery
(P1-70) Keyswitch Test Step 1. Inspect Electrical Connectors and Wiring
Remove the electrical power from the ECM.
Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Refer to the diagnostic functional test 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 connector (allen head screw) for the proper torque. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect" for details.
Check the harness and the wiring for abrasion and for pinch points. Expected Result:All connectors, pins, and sockets are completely 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 in the connectors and/or wiring.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.Verify that the repair eliminates the problem.STOPTest Step 2. Check the Battery Voltage at the ECM
Disconnect the J1/P1 ECM connector.
Restore the electrical power to the ECM.
Measure the voltage between P1-48 (Switched Positive Battery) and P1-63 (Negative Battery).
Measure the voltage between P1-52 (Switched Positive Battery) and P1-61 (Negative Battery).
Measure the voltage between P1-70 (Keyswitch) and P1-63 (Negative Battery). Expected Result:The voltage measures 24 3.0 VDC.Results:
OK - The ECM is receiving the correct voltage.Repair: If an intermittent condition is suspected, refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - The voltage is not correct at the ECM. Proceed to Test Step 3.
Not OK - Keyswitch - The voltage is not correct at the input for the keyswitch. Proceed to Test Step 4.Test Step 3. Check the Batteries
Measure the no-load battery voltage at the battery posts.
Load test the batteries. Use the 4C-4911 Battery Load Tester. Refer to Special Instruction, SEHS9249, "Use of 4C-4911 Battery Load Tester for 6, 8 and 12 Volt Lead Acid Batteries" and Special Instruction, SEHS7633, "Battery Test Procedure". Expected Result:The batteries pass the load test. The measured voltage is the minimum specification for a 12V or 24V system.Results:
OK - The batteries are OK. Proceed to Test Step 4.
Not OK - The battery voltage is low or the battery did not pass the load test.Repair: Recharge or replace the faulty batteries. Verify that the repair eliminates the problem.STOPTest Step 4. Check the Voltage from the Keyswitch
Remove the electrical power from the ECM.
Remove the wire from terminal R of the keyswitch.
Restore the electrical power to the ECM.
Turn the keyswitch to the ON position.
Measure the voltage between terminal B of the keyswitch and engine ground.
Measure the voltage between terminal R of the keyswitch and engine ground.
Turn the keyswitch to the OFF position.
Remove the electrical power from the ECM.
Reconnect all wires to the original configuration. Expected Result:Voltage is present on terminal B and terminal R at the keyswitch.Results:
OK - Voltage is present on terminal B and terminal R at the keyswitch. Proceed to Test Step 5.
Not OK - Voltage is not present on terminal B at the keyswitch.Repair: If voltage is not present on terminal B, repair the wire between the +Battery and the keyswitch. Verify that the main fuse is not blown. Verify that the main breaker is not tripped. Verify that the circuit breaker is not tripped. Verify that the problem is eliminated.STOP
Not OK - Voltage is not present on terminal R at the keyswitch.Repair: If voltage is present on terminal B of the keyswitch but not present on terminal R, replace the keyswitch. Return all wiring to the original configuration. Verify that the problem is eliminated.STOPTest Step 5. Check the Voltage from the Main Relay to the ECM
Remove the wire from the normally open terminal of the main relay.
Restore the electrical power to the ECM.
Turn the keyswitch to the ON position.
Measure the voltage between the normally open terminal of the main relay and engine ground.
Turn the keyswitch to the OFF position.
Reconnect all wires to the original configuration. Expected Result:The voltage measures 24 3.0 VDC.Results:
OK - The voltage measures 24 3.0 VDC.Repair: Verify that the circuit breaker is not tripped. Repair the wire between the main relay and the circuit breaker or repair the wire between the circuit breaker and ECM connector P1. Check the connection at terminal 1 of the machine connector.STOP
Not OK - The voltage does not measure 24 3.0 VDC. Proceed to Test Step 6.Test Step 6. Check the Voltage at the Coil of the Main Relay
Remove the electrical power from the ECM.
Remove the wire from the coil of the main relay.
Remove the wire from the main breaker to the normally open contact of the main relay.
Restore the electrical power to the ECM.
Turn the keyswitch to the ON position.
Measure the voltage between wire 322-BU(Blue) and engine ground.
Measure the voltage between the wire from the main breaker to the normally open contact of the main relay and engine ground.
Turn the keyswitch to the OFF position.
Remove the electrical power from the ECM.
Reconnect all wires to the original configuration. Expected Result:The voltage measures 24 3.0 VDC.Results:
OK - The voltage measures 24 3.0 VDC on both wires.Repair: Verify that the wire from the coil of the main relay has continuity to engine ground. If the continuity of the wire is OK, replace the main relay. If the continuity of the wire is not OK, check the fire suppression control for proper operation. Verify that the problem is no longer present.STOP
Not OK - The voltage does not measure 24 3.0 VDC on the wire from the main breaker to the normally open contact of the main relay.Repair: Verify that the main fuse is not blown. Verify that the main breaker is not tripped. Repair the wire