Diagnostic Code Decoder
Translate engine flash patterns, beep counts, and digital fault codes into plain English instructions.
How to read codes on your specific brand
Suzuki DF Series
Turn the key to the ON position. The 'Check Engine' lamp will flash. Count the number of flashes, then a 1-second pause, then the second set of flashes. For example, 3 flashes followed by 2 flashes is Code 3-2.
Yamaha EFI Models
Yamaha utilizes long and short flashes. A long flash (1.5 seconds) represents '10', while a short flash (0.5 seconds) represents '1'. Two long flashes and three short flashes would be Code 23.
Mercury Outboards
Most Mercury engines use an audible buzzer system. Listen for the number of beeps immediately after turning the key to ON. 1 beep is normal; multiple beeps indicate a specific sensor fault.
Active vs. Stored Codes
An Active Code represents a fault happening right now. The engine may be in 'Limp Mode' to prevent damage. A Stored Code is a record of a past event that is no longer occurring but remains in the ECU memory for technician review.
What is 'Limp Home' Mode?
Technically known as 'Guardian Mode' or 'Engine Protection', this is a software safety state that limits engine RPM (usually to 2000-3000 RPM) when a critical fault like low oil pressure or high temperature is detected.
Post-Decode Checklist
Many codes are caused by loose or corroded wiring connectors rather than a failed sensor.
Modern EFI outboards are extremely sensitive to voltage. A weak battery can trigger multiple "ghost" codes.
Once a repair is made, the code may need to be cleared via a specific key-cycle sequence or diagnostic software.
Common Outboard Warning Signals
The Check Engine Light
Usually a red or orange lamp on your tachometer. On EFI engines, this light blinks in specific sequences to identify sensor failures.
Beep Warning System
Mercury and older OMC engines use audible buzzers. A continuous beep usually indicates a critical overheat or no-oil condition.
Limp Home Mode
When a major fault is detected, the ECU will limit RPM (usually to 2000 or 3000) to protect the engine from permanent damage.