Mercedes 7G-Tronic 722.9 Speed Sensor Replacement Tip

Hey,

As many know it is common failure in Mercedes 7G Tronic, that internal and turbine speed sensor stop working, Y3/8N1 & Y3/8N2.
Chinese video has been online ages to replace them, but it seems much easier in video that it really is for first timer.
So i made a little DIY walktrough.



First scrape sensor pad off of sensor, gently from side to side.
(In this picture sensor is already removed)



Then place control unit over some hard block, so it wont twist.
(When you hammer sensors, be careful not to ruin ribbon pcb, when
sensor starts moving)



Give some of good tap for both of sensors, the longer is very tight!



I drill 3,5mm hole to longer sensor, so i don't have to abuse unit so much.
Hard to take picture with drill in other hand, just drill straight



I use 3mm punch to remove longer sensor.





Old sensor.



Then clean pads with sanding paper and tweezers.



After this you can give good cleaning with electronic cleaner.
I use engine sealant to glue sensors, put to sides and i put to head also for the longer sensor, which hole we earlier drilled.
Push sensor with something to make sure it is 100% seated.





Melt the new sensor a bit with soldering iron, to make sure it stays in place



Use good solder and preheat pins, solder nice balls in every pin.



Then heat with iron and use a flathead screwdriver to push gently the pads to pins.