whoover

Great information, but you say there is one Beru and two Siemens but describe two Berus and one Siemens. Which is it?

Skylaw

My06clk, brakel8

You were correct about the reset. My system came back up yesterday after about 20-25 minutes of driving (11 miles on deliberately-chosen low speed roads).

I'd had yellow "check pressure" warning lights on several occasions; I normally run my tires cold at 30 psi front, 33 rear, so ordinarily there is a 3 psi differential. At highway speeds, all will eventually balance out at the same pressure (usually 34 or 35 psi after 30 minutes or so at 70 or above). Using the "Reset" with the yellow light just resets the light, and not the entire TPMS, apparently, because the pressure readouts are instantly available after resetting the light.

MY, your observation concerning transient sensor readings triggering a warning light makes sense. I am aware of pressure changes due to driving, and I know any TPMS would have to account for it - so the most logical way to write the algorithm for warnings would use a differential between high and low, and not the actual pressure readings. However, I have had the "yellow light" and "check pressure" readout with one cold readout at 28 (i psi low), and the high at 32 - a 4 psi difference. If the system requires the differential you state, then a transient reading would explain it.

When I had readings of 27 psi (cold) on one tire, and 32 high with no warning, I did shut down and let 3 psi out of the low tire to see if I could trigger a warning. That gave me an 8 psi difference (as closely as the system reads out, anyway; of course, the actual difference could have been fractionally less) - and no warning. That's why I reset the whole system. Obviously, that kind of reset is very different from resetting just a warning light, and restoration time is far longer than initial indications normally take after starting to drive.

brakel8, I agree with you on digital tire gauges, and I use one each time I top the tires off (cold, of course). It is more accurate than the TPMS readout. However, because I apparently have the "worst of all" Beru system (I have an '05 S-Class, but do have pressure display on the dash and somewhere around a 20 minute reset time), I am going to re-set my pressures with the gauge, then re-set the TPMS again. Pressures were not precisely balanced when I reset the system, so the "baseline" is off - and indeed, all of my pressures read spot on the recommended pressures, when I know they're not. Great information.

my06clk

You're right about this.. I was thinking about that on my way home this morning that i has posted the wrong pics..and chimed in to correct this.. I was thinking moving too many files this weekend..LOL

Good info though.. except the 2004-2006 S class does display pressures on the dash'

whoover

Actually, the TPMS is inherently extremely inaccurate but very precise. But its precision means that when properly calibrated it is more accurate than a commercial digital gauge.

A TPMS sensor can tell pressure difference much more accurately than a normal digital gauge, but can't tell by itself what the absolute pressure is. That's why the manual says the same thing as brakel8: make sure the tires are at the recommended pressures before doing the reset. Once you've done that, the TPMS readings will be as accurate at that pressure and more precise about changes than the digital gauge -- in other words, more accurate. It's just a matter of calibration procedure.

I find this Beru TPMS system to be spot on. I assume that brakel8's comments about the sensors being problematic has to do with its failure mode and not with its accuracy when correctly calibrated. TPMS is one of my favorite cluster displays.

my06clk

I totally agree with you there...

Skylaw

I understand what you are saying regarding the sensing of pressure within the TPMS system. However, my digital gauge reads out to tenths of a pound, where the TPMS reads out only to the nearest pound.

LetsJet

I thought digital gauges were not very good. Does anyone recommend a certain brand? TR have a good one?

my06clk

I didn't have my 18" wheels on long enough to pay attention, but since 20" wheel don't hold the volume of a 17 or 18" wheel, the pressure swings are more significant at different temperatures ( 39 and 38 last night at 72dgees, and 34 and 32 this morning at 46 degrees till I drove for a while )... Thus, being able to measure to within 10ths of a pound for me would be nice, but not very useful.

Anything below 120 lbs is still considered to be low pressure in the industrial world, so the need to manage 28 to 40 psi in tenths of a pound also seems to fall in the useless info catagory IMO.

Frank_S500

I beg your pardon, but the antennas are within the wheelarchs. The picture you're showing are just acceleration sensors if i remember correctly.

Cheers, Frank

Frank_S500

Thought 315 MHz is for the US 433 MHz is for the rest of the world. Is it now permitted to operate radio transmissions at 433 MHz in the US too ??
Cheers, Frank

my06clk

Thanks Frank .. Please refer to post #28 I already said that... The Pics I posted are incorrect...I thought they were for the airmatic actually but now I need to verify what they actually are...

SECguy

Does anyone know if the module on my 06 s500 can be reset to read the 433 mhz sensors. I had 4 brand spankin' new ones installed on my car yesterday and I think the ones coming off were 315s - of course it took a 20 mile drive from the shop to realize something was amiss!

wweeks

I am in the same situation as I want to know if I can replace all 4 sensors and go from a 315mhz to the 433mhz. I found all 4 oem new sensors on ebay for 139.00. I contacted the dealership and they state they have no clue but to run what the "computer tells them" The Ford dealer stated if all 4 are changed the computer will reprogram to read the sensor on my Ford F350, but this is a Mercedes and you never know!

classyS

very helpful thread, now is there a way to disable TPMS altogether?? i know its an issue but less of an issue compared to other problems this car has, i decided to keep pressing R to clear the message that prompts, "tire press. control visit workshop"

thanks guys

Quadrobenz

The TPMS on the 2006 S is user friendly. It shows the individual tire pressures, is easy to reset and to "learn" the pressures. The downside is short battery life in the transmitters. I have Tire America replace mine with the tire changes. The cost is just the sensor then, I recall it is about $80 per wheel.

Vabene7

Classy,
I asked my tuner to hook up a STAR diag machine and turn off my TPMS sensor.

boop42

...and how do you know, I'm a new owner, does every Benz come with TPMS?

2000 S500...

is there a way to check if the system is running?

fxdeebee

At some point ( 2010 ? ) the Feds mandated TPMS in all vehicles built from that date, prior to that it was an makers option. To find out if you have the system, run your VIN thru any of the inline decoders ( http://carinfo.kiev.ua/cars/vin/mercedes/commerc ) and see if it was installed. You can post your VIN here and it will auto link to a decode but will be a bit general and not show everything. You are looking for code 475.


For W220 with build dates prior to 30 Sep 2000, if TPMS is installed, there should be a switch located on the console to the bottom right of the shifter.

boop42

wow..only thing is ITS IN GERMAN..LOL? but thanks..

boop42

nope no code 475...but there are some codes, that um...really?

fxdeebee

Actually, its in Russian. Right under where you input your VIN, select English and try again.

THOMPSONSPORTX

I have a 2004 cl55 low mileage , only 25k, after changing the battery and disconnecting a couple of times the car developed numerous faults, I read every post I could find and reset everything as described, being left with TPMS messages, drivers seat missing various functions, door handle lock button not working, sound unavailable and also had 2 amp battery drain on instrument cluster, which turned out to need replacing, I contacted local dealership and various specialists only to end up depressed and looking at massive costs. Feeling totally out of my depth, and not wanting to hand my car over to a possible test pilot who could justify anything, I looked on EBAY and bought a STAR system £750.00. this has been brilliant, it has paid for itself over and over, turned off the TPMS, once and for all,reset things I thought needed new modules and put me in charge of this car, I now realize that owning one of these cars without a STAR system is almost impossible.

busflier

Anybody willing to help me turn the TPMS back on with STAR in my 2004 W220? it was turned off by dealer before I purchased the car. After turning on, and if it works, I will install aftermarket sensors in tires.

Thanks!

fxdeebee

Actually... I would do the sensors before trying to troubleshoot the system. Doing it backwards wont accomplish much other than error messages about the system not working because the sensors are dead.


How firmly are you convinced that the dealer actually disabled the TPMS ? You might try pulling fuse 70 ( behind right side rear passenger foot light. #70 is 5th from the door counting towards the middle top row, count the slots, not the actual fuses ) for 30'ish seconds, put it back in, fire the car up and see if in fact it just was off line and needed a hard reset.

busflier

Thanks for your reply!

I'm putting in the sensors today. Amazon.com for $121 for four! Costco will put them in for $14 per tire. Unfortunately I just had those tires installed there three weeks ago, but did not think about this until now

I bought the 2004 S-430 three years ago from a dealer. At the time I did not know anything about TPMS (or many other things), but eventually I found out it came without the sensors, and looking at the dealer history, TPMS was turned off when they took off the sensors I guess, I imagine to avoid replacing the sensors? They probably quoted thousands of dollars to replace them and the previous owner balked .

Anyway...my local dealer will turn TPMS on for free...

Thanks again!