TPMS - Tyre Pressure Monitoring System

Installed on many BMW bikes from mid 2000's

RDC / TPMS provides the rider with information on the current tyre pressure. The data is supplied by radio sensors in the Schraeder tubeless valves fitted to the wheels. These sensors are powered by a lithium CR2032 battery with a life span of around 5-7 years. When the batteries start to fail the TPMS will take longer to come on and show a reading. This is a tell tale sign your batteries are on the way out. If one fails change both as the other can't be far behind.

My R1200GSA is a 2009 model, 7 years and my sensors recently stopped working. This leave you with the annoying yellow triangle which you cannot get rid of until the sensor problem is fixed. It comes as a shock to learn that new sensors cost around $200 AUD and having a pair fitted is likely to cost in the region of $600. So can you do it for less?

I embarked on the journey of trying to do just this and after many set backs and a lot of learning I have succeeded. So I wanted to share the learning with you and let you know that you can remedy this annoying problem for the princely sum of $13 AUD per pair and a bit of your time and effort. Oh you also need access to at least one, possibly two neat tools that the club should be able to facilitate. these being the GS-911 can bus interface and the Ateq VT15 TPMS reset device.

First a couple of myths dispelled. 

- the sensors switch off automatically when the bike has been stationery for more than around 15 minutes. This conserves battery life. They cannot be turned on by waving a magnet around them. They are re activated when the bike is moving and when rpm passes around 20-30km/h.

- sensors can be tested outside the tyre / before fitting. They do not require pressure to be activated. This is where the Ateq VT15 wake up tool comes in to play. It produces the correct radio frequency to waker the sensor which will then transmit to your on board dash IF it has previously been paired to your bike.

- your on board computer will not register a TPMS sensor that has not been paired (introduced) to the onboard computer. To make this introduction you need a GS-911

So my sensors failed and rather than fork out for new ones I tried buying some of the $20 units offered up on eBay from you guessed it China. Well suspecting some might not work and thinking that if they all did I could sell the extras I bought 4. they arrived about a month later $80 AUD delivered.

These sensors appear to be the genuine Schraeder OEM ones, albeit I suspect they are old stock or second hand units. I also found all 4 had flat batteries despite the guarantees offered on the vendors advertisement. Have you ever wondered why delivery from China takes so long? I suspect it takes just long enough for your window of time to lodge negative feedback on eBay to expire!.

So this prompted me to try and replace the batteries in the sensors. Which turned out to be surprisingly easy.

First remove the silicon/rubber coating over the battery compartment. I used the can opener on my leatherman, no kidding it worked perfectly.

Then remove the CR2032 battery using the tip of your pocket knife or a flat blade screwdriver to break the toy spot weld holding the tabs to the battery. There is one on top, visible, and another underneath that you only see if you pry the battery up on one side.

Next buy replacement CR2032 batteries WITH solder tabs, available for $2.45 from Jaycar.

Fit the battery by inserting the sensor tabs between the battery solder tabs and battery body. Then use a small clamp to hold the battery down in position and use some epoxy from the local hardware store to set the battery in position. alternatively you can simply cover the battery with a non conductive strip of plastic or similar and hold in place with fine zip ties (Pete's method - proven successful). 

Now if you have replaced the batteries in your existing sensors you only need to refit them and clear the TPMS fault codes in your on board PC using the GS-911. If however like me you are fitting newly reconditioned or different sensors you will first need to pair them to your on board computer. To do this you need the GS-911 and the TPMS wake up tool the Ateq VT15.

First connect the GS-911 to your bike and clear the existing TPM fault codes. Next place the TPMS system into learning mode (using GS-911) and then activate the new sensors using the Ateq VT15 (in or out of the tyre) I did this outside the tyre to be sure all was ok before fitting the sensor in the tyre. The next picture shows me testing this before epoxying the battery in place. I then tested it again before fitting to the tyre to be sure.

Pairing takes a couple of minutes and then up come the pressure readings. on your dashboard. 

Price for replacing my sensor 2,45 for the battery $8 for a tube of 2 pack epoxy (clear). Plus some effort to remove the tyre and fit the new sensor. I have not needed to fit the second sensor yet as mysteriously when the rear was fixed the front decided to come back to life, so I will wait and change it when I have to replace the tyre in a month or two.

The process really was quite easy and very satisfying once the correct steps were determined and the right tools were available.