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Hello All, I was looking for help or guidance and hoping maybe somebody had the same problem and solve it! I recently purchased a 2007 S550 base. When I purchased the vehicle the tire pressure monitoring system inoperative warning message was showing and light was on. I’ve had no luck getting this message to clear and the TPMS system to work. I’ve checked all four wheel sensors and they are reading accurately with good batteries. I scanned the vehicle with an autel scanner and it says the system is active and also say active on the vehicle display, but when I go drive the vehicle to get the light to go out the tire pressure monitoring system inop message comes back. I’ve also taken it to a local tire shop with no luck . Any suggestions so I’m not just throwing parts at it? Thank you in advanced….
I’m not sure, I just recently purchased the vehicle and the message was already there. I wonder if I can check the frequency with my tpms scanner? Also do you know what the frequency should be or where I could look it up?
Any way to check the frequency without pulling the sensors?
If you have an Autel scan tool, you can check the frequency. I had a problem recently with one sensor not registering, and my car giving me a error in the right rear wheel. I used my Foxwell scan tool to reset the sensor, reprogrammed the sensor previously not sending a signal with my Autel scan tool, and it was solved.
You might want to ask some local tire shops if they can scan for frequency. I don't know if it would be worth buying the equipment to check that unless you needed it for other reasons as well. A set of 4 TPMS sensors set me back $69 from Amazon. The install labor was twice that.
You might want to ask some local tire shops if they can scan for frequency. I don't know if it would be worth buying the equipment to check that unless you needed it for other reasons as well. A set of 4 TPMS sensors set me back $69 from Amazon. The install labor was twice that.
I think he mentioned he already had the scanner...that's why I suggested it. However, even if he (or anyone) doesn't, it may be worth buying--mine has already paid for itself in a month. I bought it after the dealer charged me $178 for a sensor, and I think $150 to install it. Not doing that again.
I think he mentioned he already had the scanner...that's why I suggested it. However, even if he (or anyone) doesn't, it may be worth buying--mine has already paid for itself in a month. I bought it after the dealer charged me $178 for a sensor, and I think $150 to install it. Not doing that again.
I highly doubt that all the sensors were changed, seriously, I can see one being changed but then if it was wrong only that tire would not show psi for that specific tire.
Did someone replace the wheel sensors with the wrong frequency?
I highly doubt that all the sensors were changed, seriously, maybe one sensor installed with the incorrect one but if that was so only that specific tire would not show a psi reading and the others would.
I highly doubt that all the sensors were changed, seriously, maybe one sensor installed with the incorrect one but if that was so only that specific tire would not show a psi reading and the others would.
One bad sensor would show one tire without a reading. Since all 4 sensors were producing a signal, all 4 sensors have a good battery but they are not being detected by all 4 receivers. I believe it's a frequency mismatch. This car should be on its second or third set of TPMS sensors. It's possible that the most recent set installed was the wrong frequency.
I think the system refuses to show any pressures on any wheel if one its at fault (that is the way my car did it, and indeed my BMW bike does this too) - in some perverse safety idea if one is wrong or unknown the car / bike is not safe, so only warn of the risk - don't show other are safe !
the pressure units display idea is rubbish - the car gets a grown up signal and just lies to the fool at the wheel what unit the car is set to display - they don't have PSI and F sensors and separate BAR and C ones - and if you look at the link I gave in post days ago USA moved started life with 315mhz, and had one year with they used BOTH frequencies and I presume then moved their world to the car std of 433mkz
I think the system refuses to show any pressures on any wheel if one its at fault (that is the way my car did it, and indeed my BMW bike does this too) - in some perverse safety idea if one is wrong or unknown the car / bike is not safe, so only warn of the risk - don't show other are safe !
the pressure units display idea is rubbish - the car gets a grown up signal and just lies to the fool at the wheel what unit the car is set to display - they don't have PSI and F sensors and separate BAR and C ones - and if you look at the link I gave in post days ago USA moved started life with 315mhz, and had one year with they used BOTH frequencies and I presume then moved their world to the car std of 433mkz
So it seems that from 1/2007 to 12/2009 Mercedes were fitting both 315MHz and 433MHz sensors to S-Class vehicles in the US. Do you know how I can determine which I have? My car was delivered on 2/28/2008 if that helps any. I purchased a set of 433MHz sensors online based on my specific vehicle, had them installed and confirmed that they are working. My car refuses to learn then and them, somehow, I managed to delete all sensors from the car ... and then there were none!
I have tried a Foxwell scan tool and an Autel TPMS scan tool and neither one will persuade the car to recognize the sensors. Before shelling out for another set of sensors (315MHz this time) I figured I would seek the collected wisdom of this forum.
The car is reporting code 9130 FWIW.
Last edited by baxkr; 01-18-2024 at 01:57 AM.
Reason: Additional info
lots and lots of people claim the car or indeed bikes can learn a sensor - I have NEVER seen that happen in reality - on all the vehicles I have worked on, you programme the ECU with the sensor codes of the ones fitted on the car (after waking them up - by driving or with a wake tool) - OR - you use Autel sensors that are better, cheaper and more flexible - and programme each sensor to the rubbish already inside the ECU's brain (faking the original sensors).
if you fit 315hz sensors to a 433mhz car - I GUESS the cars individual wheel receivers inside the wheel arch liners don't understand whats going on
the Merc parts dept can tell from reg or chassis number what rubbish they used when they made it
Autel's latest sensors can be programmed to 315 or 433 on the same sensor
lots and lots of people claim the car or indeed bikes can learn a sensor - I have NEVER seen that happen in reality - on all the vehicles I have worked on, you programme the ECU with the sensor codes of the ones fitted on the car (after waking them up - by driving or with a wake tool) - OR - you use Autel sensors that are better, cheaper and more flexible - and programme each sensor to the rubbish already inside the ECU's brain (faking the original sensors).
if you fit 315hz sensors to a 433mhz car - I GUESS the cars individual wheel receivers inside the wheel arch liners don't understand whats going on
the Merc parts dept can tell from reg or chassis number what rubbish they used when they made it
Autel's latest sensors can be programmed to 315 or 433 on the same sensor
Great advice, bad result (for me at least). It turns out that my vehicle is a 315MHz car and Parts Geek (bless their little cotton socks) sold me 433MHz units. Oh well.
BTW. If the wheel arch sensor is listening on 315MHz and the TMPS transmitter is transmitting on 433MHz then the wheel arch will hear nothing. It's a bit like trying to listen to the big game while tuned to the local pop station - wrong channel!! As BOTUL correctly points out using a unit that can transmit on either frequency avoids the heartache but, no doubt, comes at a slight premium. That being said the Mercedes OEM parts are $158.67 each so Autel units are probably still a steal!
One final note ... if anyone needs a set of 433MHz TMPS sensors PM me - I will have taken them back out of the car but mid next week hopefully. They're a couple of months old and all work according to my nice new shiny Autel TPMS scan tool.
Last edited by baxkr; 01-18-2024 at 02:30 PM.
Reason: More info
$100 for 4 of the either or sensor type - you need to set them up with the TPMS pad linked to a PC via a USB cable (unless posh Autel TPMS tools can also do it - likely)
$100 for 4 of the either or sensor type - you need to set them up with the TPMS pad linked to a PC via a USB cable (unless posh Autel TPMS tools can also do it - likely)
understood, what are the chances the someone installed sensors with the wrong frequency in the U.S.? Do I should ask dose it happen often?
Very high if they own a vehicle from 2007 - 2009 since MB fitted both 315MHz and 433MHz sensors during that time. I know because I was one :-( If you don't own a scanner that will read the in-car sensor you can call the parts dept of your local MB dealership and give them the VIN. They will be able to tell you.
Brief aside question. Which do I believe - the pressure from the Autel sensor or that from my little manual pressure gauge? They're off by about 3psi (the manual gauge reads 35 for front left and rear right).
PSI is especially BAD, where USA owners insist on seeing old world history for the pressure readings... if you have it on PSI it jumps all over the place and is generally always offensive !
Bar needs two decimal places to get the 'accuracy' of PSI - and as the display doesn't show them, they appear FAR more stable and it makes you happy !
mainly to stop you worrying and fiddling unnecessarily - TPMS has built in fake the displayed reading based on tyre temp - so it offsets both at cold temps and at high temps the value you see.... this makes the cluster display seem nice and steady when in reality at -10C to plus 60C (tyre temp) the PSI is really varying 8 or so PSI....
Check when the wheel tyre and air is at 23C (72F) and see how it compares with your hand held gauge....
International System of Units (SI), international decimal system of weights and measures derived from and extending the metric system of units. Adopted by the 11th General Conference on Weights and Measures (CGPM) in 1960,
for pedants - bar is still wrong - we are meant to use billions of noughts to be SI legit ....
1 bar = 100,000 pascal = 14.503 PSI
marvelous even though 1 calorie is the energy needed to raise 1 cm3 of water by 1 C we didn't bother to set pascals in the correct place ... Atmospheric pressure, also known as air pressure or barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as 101,325 Pa (1,013.25 hPa), which is equivalent to 1,013.25 millibars, 760 mm Hg, 29.9212 inches Hg, or 14.696 psi. The atm unit is roughly equivalent to the mean sea-level atmospheric pressure on Earth; that is, the Earth's atmospheric pressure at sea level is approximately 1 atm.
03-22-2023, 05:40 PM
