2009 Yamaha F40 Outboard Service Manual, Page 86Get this manual
Troubleshooting the power unit
Troubleshooting the power unit using the diagnostic flash indicator
1Connect the special service tool a
4If trouble code is detected, see "Trouble code and checking step" (4-6)
When more than one trouble code is detected, the diagnostic test lead flashes in the pattern of the lowest trouble codeAfter that trouble code is corrected, the indicator flashes in the pattern of the next lowest trouble codeThis continues until all the trouble codes are detected and corrected