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Registered 2011 SLK250
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581 Posts
Discussion Starter #1 (Edited by Moderator)
I recently found out that there are multiple types of tire pressure monitors:
470 - Tire pressure monitor (TPM) low line
475 - Tire pressure monitor (TPM) high line/mid line
477 - Tire pressure loss warner

I have 477, which warns me if a tire is loosing pressure. I do not have the ability to check the actual tire pressure.

Am I correct in assuming that option 470 and 475 allows you to actually see the tire pressure of each tire in the instrument cluster?

If so, what would be the difference between 470 and 475?
 

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Premium Member 2012 SLK350
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818 Posts
Not really sure which ones I have, but they do indicate a loss of preasure, and the pressures are indicated by wheel and preasure on the instrument cluster. The preasure level for the warning can be reset. That feature is rather helpful when it turns cold and preasure tends to drop just a pound or two...

Sent from my SM-T550 using Tapatalk
 

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Registered 2011 SLK250
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581 Posts
Discussion Starter #6
470 - sensor based fast acting low pressure notification, no pressure readings
475 - sensor based pressure readings
477 - inferred slow acting low pressure notification through wheel speed, no pressure readings
So another thing to look into, for retrofitting :)
 

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Registered 2011 SLK250
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581 Posts
Discussion Starter #7
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!
 

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Premium Member 2018 SLC43
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2,455 Posts
Well done on installing another MB option - Great write up for other owners :tu:

The facelift R172/AMG 43's all seem to have the:
> 475 - Advanced Tire-Pressure Monitoring System

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
Funny You should ask where the control unit normally resides - While lubricating the hinge of My centre arm rest, as it felt a bit "rough" :frown:
..I noted this wire:


...which led Me to explore what it was for..??


....and after popping a cover off on the under side of the centre armrest, came across the TPS control module..!!


The location kind of makes sense, as central to all 4 wheels :nerd:
 

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Registered 2011 SLK250
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581 Posts
Discussion Starter #9
Hi Trev,

The TPMS sensor may have become standard, because of more and more rigid regulations.

Still, I find it a nice and useful addition. Even now, I noticed that my wheels are not properly inflated (2.0, vs 2.3 (in the front), when cold).
I am still waiting to find a place where they use Nitrogen, to inflate them there.

As for the A2319052600 component, that is the Motion alarm system.
It detects that there is motion in the car.
When the doors are locked, and motion is detected, the alarm is triggered.

It is placed in the center console, in order to "cover" the whole car.

Your wiring seems rather unusual. Really thin, and placed awkwardly.
As your armrest moves up and down, the wire is getting bent.

My wire was really thick, and seemed to be placed more "properly", yet, I found that it broke, awhile ago, and I fixed it.
Removing the armrest lower cover, in order to have access to the whole cable, seemed really challenging, you can find more details about it here:
https://www.slkworld.com/slk-r172-general-discussion/543438-motion-alarm-sensor.html
 

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Registered 2011 SLK250
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581 Posts
Discussion Starter #10
As for the TPMS module location, WIS is saying that it is located somewhere on the underfloor, above the rear axle (docu nr gf40.15-p-5124rd).

However, when investigation that place, I could not find any holes for my cable to go through (the cable is supposed to go through somewhere, because it has that rubber thing, that fills the hole).

In the end, I placed it near the rear fuse box.

Other MB vehicles seem to be placing there as well, so I didn't worry about the signal, which also seems to be ok.
 

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Premium Member 2018 SLC43
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2,455 Posts
As for the TPMS module location, WIS is saying that it is located somewhere on the underfloor, above the rear axle (docu nr gf40.15-p-5124rd).

However, when investigation that place, I could not find any holes for my cable to go through (the cable is supposed to go through somewhere, because it has that rubber thing, that fills the hole)..
While putting a bit of C0pper Slip grease on the rear hubs, I took this picture:

Is it the TPMS module?
 

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Registered 2011 SLK250
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581 Posts
Discussion Starter #13
While putting a bit of C0pper Slip grease on the rear hubs, I took this picture:

Is it the TPMS module?
Nice! Yes! That it is! Love how answers come even after months of posting the question! :)

Do you happen to have more photos of that area?
Could you please describe the location? How do you reach it?
 

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Premium Member 2018 SLC43
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2,455 Posts
Nice! Yes! That it is! Love how answers come even after months of posting the question! :)

Do you happen to have more photos of that area?
Could you please describe the location? How do you reach it?
If You where standing at the back of Your SLK looking forward, the picture above was taken while the right rear wheel was off My R172.
(I just took random pictures under the car, to get this shot for You...!!)
The Picture shows the drive shaft and the front of the rear differential (LSD) in My cars case R)

The picture below may give a better idea:
 

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