How to repair Launch X431 smartbox board

Here is the user solution of how to repair Launch X431 smartbox board for Launch devices with serial number 98064xxxxxx or 98024xxxxxxx.


When to repair Launch x431 smartbox board?
Launch X431 does not communicate with the car. Turns on smart box resets with success but when check if ignition is on, no lights on the launch communication error.

Only power led lights up, so probably the smartbox died.


How to repair smartbox pcb?
start software then >demo > self test > and you will see if working correctly
to me sounds like some of relays is not working. will advice to do hot gun job first and re-solder all relays. (white square boxes)


Is not something which you can test yourself. Each relay works only when is simulated only certain protocol so you have hundreds of combinations. Re assuming, without protocol simulator only way of testing them is measure ohms and checking if they click and reconnect signal. Make sure that you have knowledge how to use ohm meter, and you have stable power supply of 4.5V. And make sure ‘+’ goes to correct place. Otherwise it will be costly repair.


Then check caps with beep scale, if its beeps and number is same as connected two tester pin, then you are close to fault.



Try the method above OWN YOUR OWN RISK; but it has helped the user with Launch x431 gx3 with serial umber 980640000100


But if your pcb still doesn’t work or you’re not good at pcb modification, you can buy a new original smartbox board, Launch-made. offers the Original Launch X431 Scanner Smartbox board:

x431-smartbox-board-obd365-1 x431-smartbox-board-obd365-2 x431-smartbox-board-obd365-3 x431-smartbox-board-obd365-4


This X431 Smartbox can only used on Launch devices with serial number 98064xxxxxx or 98024xxxxxxx.

Devices includes Launch X431, Launch X431 Super Scanner, Launch X431 GX3 and Launch X431 Master at


About eobd21

I am a car lover and like to repair car by myself, and know more info about car diagnostic tool and other obd2 tools, share these info with everyone.
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