TPMS 101

These devices are way too simple yet dealers and tire shops seem easily confused by them. If you are looking for part numbers specific to the Crossfire and related discussions see this post...

TPMS Parts Post

Schrader 433 2005 info here (you have to know the frequency)

If you are wondering how these little wonders work please continue reading. I hope this information will at least get you familiar with the difference between programming sensors and training the cars computer and what the shop will be doing when they say they can "do" a Crossfire.

Sensors are made in either 315 Mhz radio frequency band or the 433 Mhz radio frequency band to transmit an ID to the cars receiver. The cars receiver/computer is "trained" to listen for only the sensors on this car. Sensors are triggered to transmit by either a 125Khz radio frequency signal or a magnet or pressure changes.

Some cars are designed to display the data received from the sensor and other cars simply turn on a light when a problem is detected. Most all sensors send pressure and temperature data.

Think of each sensor as having it’s own phone number and the cars computer as having the caller ID. The cars computer was trained to listen to a specific ID associated to a specific location on the car so on cars that are capable of displaying “left front low” will do so when the ID of the left front is received. The cars receiver ignores the ID's of other car sensors nearby since it was trained to listen to only the 4 sensors on this car. That is it in a nutshell, that is all these little devices do.








Where things get mixed up is in the relearn process of the cars computer after a tire rotation or a sensor is replaced. Tire shops may have a trigger device that steps them through the year, make model of car to get the device “ready” to trigger the sensor. The trouble starts when you have a car that was manufactured with both 315Mhz and 433 Mhz sensors like the Crossfire was. The device the tire shop has might be listening on 433 Mhz when in reality it needs to listen on 315 Mhz. You see where the user has to be smarter than the box? You cannot try to trigger Crossfire sensor without listening on both frequencies to be certain the sensor is working. I recommend you have your working sensors tested to see what frequency they are on. Chrysler told me I had 315Mhz sensors on my car based upon the VIN however when tested they were 433Mhz sensors. Be sure before you buy.There are sensors manufactured like a blank CD and are designed to be cloned to the cars original sensor ID. The blank slate clone-able sensors are usually double the money of the non clone-able (ID already in them) sensors. This sounds good in theory because you take a known ID for a wheel and make the new sensor that same ID eliminating the need to see the dealer to put the cars computer into learn mode. Other threads have not reported success going this route. One tech support person I talked to says it may have something to do with the frequency tolerance (read accuracy) of the new sensor. It may be too far off frequency for the car to accurately receive the data. It could be as simple as the protocol used to transmit the ID is not compatible with the Crossfire but it seems odd a manufacturer would say they fit the Crossfire but cannot communicate with the receiver.

So when talking TPMS with a tire shop or the car dealer please ask them to be very specific when you hear the phrase “program the sensors” because it could mean one of two things. Clone-able sensor equals program the sensor to the original sensor ID which is way different than training the cars computer to the ID of the sensor. Sometimes in hearing them speak you will get a glimpse of just how tech savvy they are….. or are not!

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From My Friend Clint, more great TPMS info;

Hello CrossfireForum!

Been a while since I checked in here, nice to be back. A scan of recent posts lets me think I can add a little help, although what is here looks accurate. I just put a file into the collection over on that FB place with the summary below. Main points offered to you here are that the cloneable sensors go by EZ-Sensor 33700 when made (by Schrader) with the aluminum clamp on valve stems (which should go on all Crossfires) AND wonder if anyone in the US or Canada has ever found they really have 315 MHz sensors? (Which doesn't matter with the EZ-Sensor 33700, can go either way).

Crossfire TPMS (Tire Pressure Monitoring System) Information

Summary: Two paths available to have the TPMS function with new sensors.
Path 1) Use Chrysler dealership (ONLY) computer to put Crossfire into TPMS Relearn mode, teach the car the new sensor IDs.
Path 2} Have new sensors CLONED to use the same sensor IDs as previously learned sensors.

Path 1 Expanded Information

The SLK R170 had no provision for TPMS, so Chrysler adapted an existing Chrysler TPMS system into Mercedes electronics for Crossfire. Wheel sensors were the same as used in Jeeps, minivans, Viper, Prowler, others back at the early 2000's start of TPMS. Wheel sensors at that time required a magnet to trigger a signal transmission from a non-moving sensor, later versions added capability for triggering by LF (Low Frequency) radio signal from most TPMS testers. Some original Crossfire sensors might still be triggered only by a TPMS magnet, not by a tester radio signal, so ask that anyone testing an original sensor try with a magnet before deciding it cannot be read at all. These sensors have a fixed sensor ID code when manufactured, so the Crossfire must be taught this code for any such new sensor. The latest Mopar number for these sensors is 52088990AE, which is made by Schrader and the same as a Schrader 20028 (except for color).

The ONLY way to teach a Crossfire new sensor ID codes is with a Chrysler dealership computer diagnostic tool. Until sometime in 2017 this had to be the old Chrysler DRB III with a Crossfire software card plus the Crossfire-Sprinter Multiplexer cable. Many Chrysler dealerships never sold any Crossfire cars, never bought the special Crossfire diagnostic and repair tools, so never had this equipment. Others might have had it, but the equipment went unused or lost after the DRB III was superseded by a different Chrysler dealership diagnostic system in 2007. Only during calendar 2017 was the current Chrysler dealership diagnostic system, wiTECH 2.0 with the microPod II, updated to cover all Crossfire model years. Many dealership service people do not know this Enhanced DRB III Emulator function is available on their current system, since it is only required to service older vehicles. But every Chrysler dealership should have the capability. The downside is that nearly every dealership will charge at least an hour diagnostic labor time - over $100 USD - to plug dealership diagnostic equipment into your car. Even though the whole relearn process should take a maximum of 5 minutes after plugging in, to walk around the car triggering each wheel sensor to be learned by the car system.

Path 2 Expanded Information

TPMS technology has evolved a lot since 2003. Single part number multi-protocol replacement sensors are available which can be programmed, and possibly cloned, to work on over 90% of cars on the road. Technology leader for this is the Schrader EZ-Sensor 33500. Other brands of aftermarket sensors with similar capabilities are available, and a tire shop needs to have corresponding equipment to program and clone the particular brand of sensor. Mopar actually sells this programmable and cloneable EZ-Sensor 33500 with a rubber valve stem as their MAGNETI MARELLI OFFERED BY MOPAR part number 1AMTP3350A. To keep the Crossfire clamp in metal valve stem may require Mopar Aluminum Valve Service Kit - 1AMTP3400A. The Schrader number for the kit to convert the EZ-Sensor 33500 to have a metal stem is 34000. Not only does this metal valve stem match the original style, clamp-in stems are recommended for any application with speed capability over 115 mph. The EZ-Sensor 33700 is the same cloneable sensor with the metal clamp in stem.

As mentioned in Path 1, the original sensors might require a magnet to trigger a signal transmission, so ask for that before deciding the sensor ID cannot be retrieved. Sensors can transmit their IDs to the handheld tester place right next to the wheel for at least several months after the battery power is too low to signal to the in-car receiver up by the rear view mirror. Another detail of possible use: factory sensors had a label on the sensor body printed with the ID. Very few tire shops will be able to use this text ID to clone new sensors, though. They, and their equipment, may only be able to record IDs by radio transmission, then use those recorded IDs to clone new sensors.

Final point about cloned sensor IDs: if you have additional wheel sets for seasonal tires, track, etc. matching IDs will enable TPMS function after wheel swaps without further hassle.

Copied from post 49;

Not to give the tire shop folks more slack than they deserve, but there are even more chances for confusion. Several varieties of "programmable" TPMS replacement sensors are on the market, to deal with the vast number of sensor part numbers from car manufacturers. So instead of stocking several hundred different sensors, a tire store can tell (program) a replacement sensor to behave like, for instance, the old original Chrysler type TPMS sensor used on the Crossfire, 52088990AC (how many have found another sensor in their Crossfire? Anyone with a 315 MHz sensor?) versus another sensor.

Most of these multiprotocol sensors have their own fixed ID of eight characters, decimal numeric for Crossfire sensors I have seen, sometimes hexadecimal. A few also have a blank sensor ID which can be cloned to broadcast the same sensor ID as the original sensor which the car module already is looking for.

Again, many tire store people may not understand this, but so it is. My local Belle Tire used to carry Orange Electronic programmable sensors, but now uses another brand of multi-vehicle application sensors from Dynamic, which may not be cloned. Dynamic sensors say right on the box "A vehicle relearn procedure is required to complete the installation."

Since August 2015 a programmable cloneable replacement sensor is marketed by Schrader, their EZ-Sensor 33500. This one can not only be told to use the protocols of many different OE sensors, but can also use either the 433 MHz (all Crossfires I know about in North America) or the 315 MHz which is supposed to be in some Crossfire cars. The new EZ-sensor® part number 33500 replaces SKUs 33000 (315MHz) - 33200 (433MHz), which can also be used in a Crossfire.

Advantage of these blank ID cloneable sensors for Crossfire: if new sensors are installed with the same IDs as the old sensors - no DRB III plus multiplexer plus card required! The vehicle module sees the same old IDs, and carries on! Note that sensors on my Crossfire could be read by the handheld TPMS diagnostic tool more than two months after the vehicle system stopped seeing the signal. Although a couple of them did wait until "woken up" by the TPMS magnet before they broadcast their ID. [My old factory sensors also had labels on the sensor body with the ID printed - but that's for another post.]

There, that's a lot of what I had to say about "programmable sensors." And it very well could happen that a Discount Tire store (they do have the EZ-Sensors) could replace one or more of your low battery sensors, clone it, put the ID into a new sensor, and have you back with a functioning TPMS.

 

Simply put the sensors that are known to work are the OEM sensors and the Schrader EZ sensor#20028 that can be fitted to some Crossfires. The Schrader EZ sensor#20066 should work but no one has said they do.
Only the dealers are known to be able to program them.

This info was available in 2010 and has not changed. See post.

 

Here lies the danger in terms 180, both the 20028 and the 20066 are NOT "programable" sensors. They have their own unique ID from the manufacturer. The cars receiver needs to be trained to the new ID of the 20028/20066's so in all reality the dealer is not programming the sensors. The 33100 is the schrader programable sensor and the car dealer would not be programming it, the tire shop would match the original sensor ID to the new blank CD type programmable sensor. See the difference? And confusion?

 

Semantics, by program I mean programing to get them to work. The dealer has to go into the cars brain to do that and that is the reason the dealer has to do it as nobody else can.

The 33000 series have not been shown to work at all. I would only suggest the EZ-sensor and the OEM numbered parts.

Your explanation is too complicated and a bit ambiguous but I'll let that pass. I did all this five years ago and we still keep coming back to questions on it.

 

Well here's something new then.. what Mercedes has the same TPMS system that we have? LOL

 

Proper terms = proper understanding. I have given you the tools to use proper terms from the original post, no translation or follow-up posts required.

 

Yeah whatever you say, I gave all this info a long time ago, so you are 5 years behind the times.
Can you see what's wrong with your post?

 

Guys I just put some Brabus Monoblock V wheels on my car and the stock sensors collar was too large so I couldn't put the stock sensors on and my tire pressure light is tripped obviously. What pressure sensor do I need that will fit the Brabus wheels and will work with our car?

thanks

 

Seems the Schraders are the only "known" to work.. have no clue about fitment with your wheel. IIR Corvette's at one point had them "strapped" to the center barrel of the wheels. So silicon and large wire tie ?

 

See 180's post here for part numbers, the later ones show what worked on my car and the procedures used..... https://www.crossfireforum.org/forum...tml#post462951

There is no way I would trust strapped down, glued down or tywrapped down sensors.

 

Are you sure?
The collar screws on to the normal sized stem from the outside, it does not go through the hole. The rubber seal is the same size as the old style rubber seal. This picture shows the rubber stem, ours use the metal stem that is screwed on from the outside, in either case the stem is put in from the inside and pulled into the hole just like the regular stems in the old days.

I'm not saying these ones work, 20028 work and they are AirAware series, these 330000 series should but have not been proven, they are shown for fitment look only.

 

What did you spot?

 

You have fixed it after I first mentioned the ambiguity.

 

20028 series..

 

Corvettes did..

 

You sure this didn't come off a dogs neck?

 

Yup seen 'em, that's why I wouldn't trust them. Say you get your new tires put on and have a great road force balance. Everything rides smooth as silk until one day one of those decides to slip and turns 150 degrees from where it started. Now you have a wheel vibration and gotta take the whole thing apart to fix it.

 

20028 ONLY if your Crossfire has 433 Mhz Sensors originally installed. Have a tire shop test the ones on the car first to see what frequency they are.

 

Brabus says I need to go to a Merceds dealer and get the pressure monitors because Mercedes ones are the only ones that will fit the Monoblock V wheel. Will Mercedes sensors work with the Xfire?

thanks

 

Theoretically any sensor of the proper frequency of the receiver will work per TIA chart. If it were my car I would find out the frequency of the current sensors then buy the Schrader in the same frequency (if they fit) and have someone with a DRBIII tool train the cars computer. (Known to work)

So you could get the Merc. Sensors of the same freq as you have now then have the Chrysler dealer train you car to them. With full refund rights if it doesn't work. (Your experiment)

The R170 does not have TPMS.