I am now proudly presenting the successful retrofit of the Tire pressure monitor (option code 475).
The following parts have been used:
A0009007000 - Control unit (bought for 5 EUR on the second-hand marked, costs 150 EUR new)
A0019903256 - Clip nut
A1725404707 - Wiring harness (bought new for 10 EUR, manufacturing took 4 weeks)
A0009050030 - Tire pressure sensor (bought used for 12 EUR each, costs around 55 EUR new (each))
The hardest part was obviously guiding the cable, from the trunk, to the driver side seat, below which the X30/30 (CAN E) splitter is located at.
I wouldn't had done it, had I not been doing the wiring for the Blind Spot and DAB options at the same time (which were also completed successfully).
The Control unit module has 4 wires, with the following colors:
- Yellow/Red - Power - goes to rear SAM to fuse 70 (5 amp)
- Brown - Ground - goes to ground point W32/2, which is on the wall, behind the passenger seat
- Green/White
- Green - Both go into connector 13, of the CAN E splitter, below the driver side seat (you will see a bunch of other green/green-white cables connected there)
I couldn't find the exact location where the control unit is supposed to be mounted (StarFinder seems innacurate), so I placed mine by the rear SAM, in the trunk (where many other Mercedes vehicles also place theirs).
In terms of the sensors, for those that don't know, they are wireless sensors, these are working at a frequency of 433 MHz. Their batteries is said to last for 5-10 years.
I removed my rubber tire valves, at a tire shop, and replaced them with these sensors. The tightening torque is 8 Nm.
In terms of coding, if you will do it online, you will need to remove code 477, and add code 475 to VeDoc.
Then do SCN online coding of the CGW.
If doing in Vediamo, you will need to change the settings in the CGW, as shown in the image (yes, that's the only thing that needs to be done.
Afterwards, I rode my car for 5-10km, and then the sensors, and their relevant pressures started appearing on my IC, under Service/Tyre pressure menu.
In Xentry, I have learned the following:
If the sensors are not picked up automatically, by driving the car, you can manually teach the control unit about their existence.
You have the following ways:
- You read the code from the sensor, and input it manually into Xentry
- If you have already mounted the sensors into the tire, and don't know the code, you could:
- Use a tire sensor reader, which will tell you the exact code (more expensive), OR
- Start the actuation procedure in Xentry, for each tire; Xentry will tell you to loose 30% of the pressure from a specific tire. Then it should recognize the sensor, and will recognize at which tire it is positioned.
I have also learned about gas types in tires.
You could either use Oxygen or air (tirefit), and input that in your tire.
Or you could use Azote, which is far superior to Oxygen, because it doesn't heat as much, when driving, and the pressures in the tire will be more constant.
As always, weigh in your options, double check if parts fit your vehicle, and most importantly, have fun, learning new things!