Replacing Front Wheel RDC Sensor

[darrell]

The last 3000 miles my front tire pressure sensor has shown blank from time to time. Today when the mechanic attached my bike to the BMW computer during a major service it showed the sensor had defaulted 57 times. My back wheel has shown blank a couple of times only so did not address that one but likely next tire change. Mechanic installed a new sensor and reprogrammed it. A call to the extended warranty company got immediate approval that it was covered cost wise. Extended warranty company was billed $224.74 for the part and 0.6 hour of labor or $71.40. So close to a $300 bill if paying for myself.

They allowed me to have the faulty sensor. I will be sending that to a forum member who is going to see if he can replace the battery in the faulty sensor and have it work. I’m sure he will update everyone if he gets it to work with just a battery replacement. He might even have a part time job if members send their faulty sensors to him along with a $50 or $100 bill so he can repair vs buying a new $225 part.[attachment=204]

[Grumpy Goat]

Great update on this Darrell - thanks!

[Grumpy Goat]

They allowed me to have the faulty sensor. I will be sending that to a forum member who is going to see if he can replace the battery in the faulty sensor and have it work. I’m sure he will update everyone if he gets it to work with just a battery replacement.

Well, it took over 2 years to get this done, but I had not forgotten to check it out, Darrell. The problem is not the sealant but the battery connectors to the motherboard circuitry of the sensor itself. It's all in this short video.



There is another video in which the guy worked on a different sensor and managed to get the battery out, breaking the battery terminals off without breaking the terminals from the motherboard. The battery in his sensor was a CR2032 with the welded-on terminals and they are oriented differently, so that when he pried the battery out, he somehow did not break the connection to the motherboard. In my case the welds were very hard to break delicately and the risk of separation from the motherboard is high. YMMV.

[Lee]

This spring in Texas I would get 2 dashes for the front tire when checking tire pressures when first taking off in the morning. That wasn't a big deal because I could check the pressure with a gauge.
What really bugged me was the warning triangle would come on several times a day.
I like the safety feature of knowing if I picked up a nail during the ride so I did not wait for a tire change to have the TPM changed.
After the trip I rode down to KC and had it changed.
Half hour labor was $60 and TPS was $188.70 Total with tax was $263.20.

Our bikes were six years old when traded. 58,100 miles on mine and 54,750 miles on Deb's.

Car TPMs last longer. Deb's car is 14 years old with 65,000 miles and so far we have only changed one TPM. I was surprised the car TPM was slightly smaller than the bike TPM.
I was not surprised the Chevy TPM was a lot cheaper than the BMW TPM
My previous Equinox did not need any TPMs in 10 years and around 65,000 miles.

[Grumpy Goat]

Car TPMs last longer. Deb's car is 14 years old with 65,000 miles and so far we have only changed one TPM. I was surprised the car TPM was slightly smaller than the bike TPM.
I was not surprised the Chevy TPM was a lot cheaper than the BMW TPM
My previous Equinox did not need any TPMs in 10 years and around 65,000 miles.

My 2010 GMC Sierra truck with 98k miles has had 2 sensors replaced so far and another one is apparently "iffy" (showed one warning on the dash so far). The guy at Discount Tire was trying to sell me a set of 4 for the price of 3 (each one is $65) since (according to him) if I replaced one at a time the others would soon follow. I declined.

One the RS, I like the fact that it is always on when the bike is on, and gives warning when there is the start of a puncture - gives you the chance to get to the side of the road and inspect. It is also internal and does not impede tire inflation.

I have an excellent and more cost-effective screw-on FOBO TPMS on the Tracer which is just as good [i]except[/i] you have to remember to turn on the app in order to get any warnings. Inflating the tire is also more cumbersone as you have to take the sensor off with a special wrench (security measure). Aside from that it also enables me to check the pressure via Bluetooth at any time as long as I am within range. Naturally the bike does not have to be on.

[darrell]

Wayne thanks for playing around with this one I replaced at 90,200 miles. This first one was covered by my extended warranty with After Care. At 128,000 miles I replaced the same tire unit as it failed. With BMW’s 2 year parts warranty they paid for this 2nd replacement. Closing in on 6 years with the bike and the rear unit continues to work fine.

My 2010 Ford F-150 with 69,000 miles has not given me any indications they need replacement.

[mspratz]

The front sensor on my 2016 RS was faulty from the day I rode it home. I would see --- about 90% of the time, and a reading 10%. The dealer replace it under warranty, but for most of the mechanic's test ride it was working, and it only cut out at the end, so that was lucky. Recently I saw the --- again a couple of times from the front sensor. I guess I might be up for a new one soon.

[Grumpy Goat]

The front sensor on my 2016 RS was faulty from the day I rode it home. I would see --- about 90% of the time, and a reading 10%. The dealer replace it under warranty, but for most of the mechanic's test ride it was working, and it only cut out at the end, so that was lucky. Recently I saw the --- again a couple of times from the front sensor. I guess I might be up for a new one soon.

Unless there was a way to test whether the "---" reading means low battery or a fault on the sensor's circuitry, it would be easier to assume that it was due to a low battery and replace it at cost under warranty, especially if the failure rate (out of the dealership) was low.

Root cause could be that these sensors are sitting idle in the parts bin common to several models, until they are installed on the assembly line. Maybe they sit for years inside the sensor after sitting for some time on the shelf at Maxell (or whoever is the supplier). The voltage does not have to drop too far before the "---" is shown.

I was also thinking ... if the sensors have to be "woken up" (using a wake up tool or a GS-911), maybe the "---" could also mean that they have somehow "gone to sleep", and rather than replace the sensor right off the bat, maybe first try and wake it up and if that fails then replace the battery or the whole sensor.

[MrVvrroomm]

GS-911 will not wake up TPMS

[Grumpy Goat]

GS-911 will not wake up TPMS

True, but from what I read I think you can manually enter the sensor's ID number and the system will then recognize it ...? I have not done this myself so I don't know from personal experience.

[MrVvrroomm]

True, but from what I read I think you can manually enter the sensor's ID number and the system will then recognize it ...? I have not done this myself so I don't know from personal experience.

This statement is true. You can manually enter a valid sensor ID.

You'll need to wake up the sensor to know it's ID unless you have it documented somewhere.

[Grumpy Goat]

This statement is true. You can manually enter a valid sensor ID.

You'll need to wake up the sensor to know it's ID unless you have it documented somewhere.

The instructions from Hexcode are pretty good and they show how to manually enter the sensor ID that is typically included in a label on the sensor. Even some of the aftermarket (Chinese?) sensors have the sensor ID on a label, although the pictures of some of those sensors show no label so a wake-up tool may be needed. I see that Hexcode even suggests another way to wake up the installed new sensor as:

THE CORRECT ALTERNATIVE, also known as the "ALERT method" is to let the air out of the wheel rapidly (we simply depress the valve for around 10 seconds)... this rapid fall in pressure wakes the sensor and places it in an Alert mode, where it starts sending its data (which obviously includes its Sensor ID!).

So it looks like one could even do this without a wake up tool ... again I have not done this myself.

[Lee]

I was also thinking ... if the sensors have to be "woken up" (using a wake up tool or a GS-911), maybe the "---" could also mean that they have somehow "gone to sleep", and rather than replace the sensor right off the bat, maybe first try and wake it up and if that fails then replace the battery or the whole sensor.

I think Bruce is saying the GS911 will not wake up the TPM because the number on the original TPM is unknown.