Tyre Pressure Sensor Wake-up Tool and Sensor Battery Replacement

Dr. Strangelove said:

so, with that gizmo you can get your TPM to read without rolling? How is the GS911 involved?

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Most people would have their bike to a BMW dealer to have the TPS replaced.

They would take the tyre off, replace the sensors. Once in place, tyre back on, pumped up, the bike would then be connected to the BMW computer.
A 'special' BMW wake up tool would be used, pressed near the sensor in the wheel, wakes up the sensor so information such as the sensors serial number is sent to the receiver on the bike.
This is done for the rear and same process for the front.
The bike needs to learn the new sensor, so on the bikes instrument dial, you then see the front and rear tyre pressure reading.

If you have a GS-911 and computer you can do the same.

The nearest BMW dealer is 3 hour ride away, and it means taking a day off work as the BMW mechanic does not work weekends.
The sensors for me are more cost effective bought from England.

There are a few wake up tools and they can be expensive...some don't work......this one worked and for little cost.

I got to thinking about the issues with my RDC today and decided to investigate further.

I've been suffering two error conditions:
- no reading from the rear sensor, just dashes
- an over-pressure fault condition for the rear tyre, with the bike thinking the pressure is 5.1 bar (which, of course it wasn't - normally about 2.9 bar)

The second condition has been annoyingly present for a couple of days, whereas previously it has come and gone randomly.

I checked it out with the GS911 and the fault indicated interference/lack of communication with the rear sensor. I presume if there had been a low battery condition at any stage that also would have been logged. The front sensor is working fine and research indicates the internal batteries should last about 10 years. So it looked to be either or both of:
- the rear sensor not switching in (or staying on) with wheel rotation
- a communication issue with the rear sensor.

I did consider a potential fault with the RDC control unit, so pulled that out and opened it up. There was no evidence of moisture ingress/corrosion as I'd seen on YouTube videos with BMW car units.

I turned the ignition on with the RDC control unit absent and the fault readout on the Nav VI showed an over-pressure fault for both rear and front tyres. This made me hopeful that perhaps it was a connector issue at the RDC control unit. I also pulled the ECU connectors and reconnected them in case there was a connection issue there.

I put everything back in place and took the bike for a test ride. The rear sensor over-pressure condition remained for a while and then disappeared, with the pressure reading appearing on the instrument display. I thought I'd cracked it, and gazed lovingly at that readout as I proceeded on my errand. I must have taken my eyes off it too long at one stage though, as the rear pressure readout had returned to dashes.

Hopefully I have cured the communication issue that causes the over-pressure fault and simply need to replace the rear sensor. As noted earlier, I've procured a couple sensors from China off eBay (they even have the BMW part number and Schrader embossed on the side ...) and when I get a chance I'll pop the tyre bead and swap the old one out.

Further to my posts above, I haven't yet replaced the original sensors with the Chinese versions – the latter probably have flat batteries by now.

The pressure reading issue continued sporadically so I got thinking about whether it is one of the sensors (rear) or a channel issue with the RDC module. To isolate this, I got out the GS911 and my sensor wake-up tool and attempted to swap the sensor assignment front to rear (so when all is working the front should then read 2.9 kPa and the rear 2.5). I failed at this, not being able to work out how to achieve it before beer-o'clock ticked by. At the same time, I'd bought a couple tabbed lithium CR2032 batteries to replace those in either the original or Chinese sensors should I wish to.

Well since jiggering around, including using the wake-up tool on each sensor, they've been performing flawlessly. It may have been the threat of replacing the batteries, or the indignity of potential Chinese sensors being fitted to the bike that did it, or some kind of reset invoked by the wake-up tool – I don't know. But if yours are playing up and there hasn't been an instrument panel sensor battery warning, maybe try irradiating each sensor with the wake-up tool. It's cheap and won't harm anything. Let me know how you go.

Folks, not sure if this is the appropriate thread but I have been suffering from the rear sensor intermittently "going missing in action" which results in the yellow triangle etc. This is really annoying as the tiny clock gets even smaller, and from time to time it would magically rectify itself. Anyway I did not get any low battery signal, but did a tyre change yesterday and replaced the RDC battery. Just be a little careful digging out the plastic resin. See photo's. Worth noting is that the battery is NOT a CR2032 but a CR2050. This means that it is 5mm in height as opposed to 3.2 mm in height. The hole for the negative side is recessed to fit the 2050. The 2032 looks like it is held up, so I made a small plastic disc and pushed it under the lower tab, to lift it up. Hot glued the lot together, (I used a match to hold the positive tab in place then snipped it off) and hey presto, both RDC reading fine over 30 mins ride. No need to do a "wake up".
I gather that the only performance difference will be about 30% shorter life, ie maybe 6 years. I think I can handle that.