866189T04 Mercruiser MODULE ASSEMBLY, ECM

Table 2
Troubleshooting Test Steps Values Results
1. Check for Active or Recently Logged Diagnostic Codes
A. Connect the electronic service tool to the diagnostic connector. Refer to Troubleshooting, "Electronic Service Tools".
B. Turn the keyswitch to the ON position. If the engine will start, then run the engine.
C. Monitor the electronic service tool for active and/or recently logged diagnostic codes.
D. Turn the keyswitch to the OFF position.
Diagnostic codes
Result: A 1221-2 diagnostic code is active or recently logged.
Repair: Make a note of all other active or recently logged diagnostic codes. Troubleshoot all other codes before continuing this procedure. Refer to Troubleshooting, "Diagnostic Trouble Codes".
If 1221-2 is the only active or recently logged diagnostic code, proceed to Test Step 2.
Result: A 152-2 diagnostic code is active or recently logged.
Repair: Make a note of all other active or recently logged diagnostic codes. Troubleshoot all other codes before continuing this procedure. Refer to Troubleshooting, "Diagnostic Trouble Codes".
If 152-2 is the only active or recently logged diagnostic code, proceed to Test Step 3.
Result: A 166-X or 2840-12 diagnostic code is active or recently logged.
Proceed to Test Step 4.
2. Clear the Diagnostic Code and Attempt to Start the Engine
A. Use the electronic service tool to clear the 1221-2 diagnostic code.
B. Turn the keyswitch to the ON position. If the engine will start, then run the engine for at least 10 minutes.
C. Operate the engine over the full duty cycle to replicate the conditions in which the fault occurred.
D. Stop the engine. Turn the keyswitch to the ON position.
E. Use the electronic service tool to check for an active or recently logged 1221-2 diagnostic code.
1221-2 diagnostic code
Result: The 1221-2 diagnostic code is no longer active.
Return the engine to service.
Result: The 1221-2 diagnostic code is still active.
Proceed to Test Step 3.
3. Check the Battery Supply Voltage to the ECM
A. Check that the ECM is receiving the correct battery voltage. Refer to Troubleshooting, "Electrical Power Supply - Test".
Battery voltage
Result: The ECM is receiving the correct voltage.
Proceed to Test Step 4.
Result: Make any necessary repairs. Refer to Troubleshooting, "Electrical Power Supply - Test".
Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.
If the diagnostic code is still active, proceed to Test Step 4.
4. Re-Flash the ECM
A. Ensure that the correct rating of flash file for the engine is installed.
B. Ensure that the latest software is installed on the ECM. Refer to Troubleshooting, "ECM Software - Install".
C. Turn the keyswitch to the ON position.
D. Use the electronic service tool to check for active diagnostic codes.
E. Turn the keyswitch to the OFF position.
Diagnostic codes
Result: The diagnostic code is no longer active.
Use the electronic service tool to clear all logged diagnostic codes.
Return the engine to service.
Result:The diagnostic code is still active.
Proceed to Test Step 5.
5. Check if a Replacement ECM Eliminates the Fault
A. Contact the Dealer Solution Network (DSN).
B. If the Dealer Solution Network (DSN) recommends the use of a replacement ECM, install a replacement ECM. Refer to Troubleshooting, "ECM - Replace".
C. Use the electronic service tool to recheck the system for active diagnostic codes.
Diagnostic codes
Result: There are no active diagnostic codes with the replacement ECM.
Repair: Reconnect the suspect ECM. If the fault returns with the suspect ECM, replace the ECM.
Use the electronic service tool to clear all logged diagnostic codes and then verify that the repair eliminates the fault.
Result: The diagnostic code is still present with the replacement ECM.
Contact the Dealer Solution Network (DSN).