TPMS - Again on my LEMON. 4 times 37,000 miles

[DRM]

I'm kind of late to the thread, but it's worth mentioning that you aren't the only one with this recurring problem. I've been through at least 4 replacements of the TPMS if not more. Currently have the "TPMS Hardware Error", but am waiting for next years service to do something about it. Roadster #619...
//dan.

 

[wiztecy]

Ok well you're good with tinkering and understanding this stuff. Didn't know it had an external antenna, sothen it should be fine. If the antenna was on the board and they coated it, that would throw the reception off.

 

[scotty2541]

Ok well you're good with tinkering and understanding this stuff. Didn't know it had an external antenna, sothen it should be fine. If the antenna was on the board and they coated it, that would throw the reception off.

Well, so far, so bad...

I powered the unit up on my workbench. The unit is a three wire device, +12, Gnd, and some communication line. There is a 5V regulator which is working fine. The communication line was silent as it sat on my bench. I am guessing it needs to be polled.
The communication line was idle at 12V. And there is a level converter 5V for the logic.

There is a 8Mhz osc that was flipping from about a 5V swing to about 1.75V... Seemed to be changing due to pressure on the board. But I don't know which is correct. (If a bad connection was loading it, or was unloading it...).

There is also a 13 Mhz osc/tank, but it was silent.
The osc/tank is just a two terminal device, and the component designations are Y1 and Y2... not really helpful.

I reinstalled the unit, and measured the voltage, and it is powered when in the car. I didn't drag my scope under the car, which would be the next step.

Here is the unit lifting out of the case, where you can see the antenna wire along the left and back.


And here is a view of the board after I cleaned it ("Goof-Off", acetone, denatured alcohol... just not all mixed together).

The circuit board antenna, and the wire. I also destroyed a cap when cleaning it, but it's just a power filter cap on the output of the regulator. And 220uF, 16V are about as common a leaves...

There is more I could do, but I'm busy now with lots of stuff. I'm taking the car in to replace the brand new defective cabin blower, and I'm gonna tell them to fix this under warranty, since they convinced me to play them $500 last time only to have it fail 1 year, 2 weeks later. And the old adviser told me once I paid to have these replaced, I should be good for 4-5 years. Although I doubt they will do that, or show any kind of flexibility. Add to that the fact that they make me wait another 2-3 weeks after I call before they even get me in... this service center is really crappy customer service.

Maybe I'll hack at it more in December. I'd love to get a schematic of this thing. Or a manual. Anyone have any leads on that?

 

[wiztecy]

Nice going on the tear-down and inspection. Seems like you're doing the right debugging techniques on this thing. From your pic do you see those, what appears, to be very bad solder points on two of the. The lower half of the chip which has connections on all four sides and the chip to the left of it. Looks like some bleeding of the solder but its hard to tell from the pics really, couldn't get good resolution on the zoom. How do they look to you. I'm sure you've inspected all that. Thanks for posting the pics & data.

 

[scotty2541]

Nice going on the tear-down and inspection. Seems like you're doing the right debugging techniques on this thing. From your pic do you see those, what appears, to be very bad solder points on two of the. The lower half of the chip which has connections on all four sides and the chip to the left of it. Looks like some bleeding of the solder but its hard to tell from the pics really, couldn't get good resolution on the zoom. How do they look to you. I'm sure you've inspected all that. Thanks for posting the pics & data.

I have a lot more pics. But I need to resize them, and re-take some to get a better focus.
The four sided chip, on the bottom did have ugly looking solder connections. I re-heated them, and even accidentally bridged two pins, so I have to braid them up and retouch. The Y2 device is the one that was oscillating. The other big rectangle is Y1 and it had nothing. You can't see them, but at the correct angle, all chips have stamps that are readable. Y2 is stamped 8 Mhz, Y1 is 13.5 Mhz (Plus other markings).
I don't have the board at work, so I can't say much about it now. I can list all the chip IDs later when I get home.

 

[ML Auto]

You could always pull out the good front antenna and compare them side by side.

 

[scotty2541]

You could always pull out the good front antenna and compare them side by side.

I was considering this. But my weekdays are kinda full, so that restricts the time I have to screw around with this thing.

Also, I was concerned about removing and trying to test the good unit. I didn't want to damage it when prying it open, the board is still covered with rubber spray, and it likely wouldn't attempt to send any data unless the host polled it. I'd rather pull the dash and attach my scope to the main unit, if I knew where it was.

Lastly, getting under that car is a pain when I only have one little scissor jack from my Toyota.

The car goes in tomorrow for the blower motor anyway. Lets see if the service center gives me any kind of a break on fixing the TMPS since it died one year and TWO WEEKS after I paid them to fix it last time (Hint: high probability they won't). I'd almost prefer to load the car on a flatbed and take it to the next state to deal with better service advisers than these guys. At least with my, Toyota when one service dealer screwed me around, I could just take it to another place 7 miles away.

 

[scotty2541]

You could always pull out the good front antenna and compare them side by side.

MLAuto... are you a service center? For Tesla? Could I purchase a replacement unit from you? Or do you know where I can buy one from another source? Tesla is a little steep on some of these things ($1 airbag clip from Lotus, I think they charged me $4 each)

 

[DeedWest]

On a completely unrelated note, I saw your car in the SC on Friday morning when I dropped my Roadster off for her annual service. Yours is absolutely gorgeous!!! Electric Blue has always been my favorite color since I first heard of the Roadster. Nice to see a 2.5 in person in that color.

 

[scotty2541]

On a completely unrelated note, I saw your car in the SC on Friday morning when I dropped my Roadster off for her annual service. Yours is absolutely gorgeous!!! Electric Blue has always been my favorite color since I first heard of the Roadster. Nice to see a 2.5 in person in that color.

Thanks. Was it by the door, Zep? working on the cabin blower?
I guess that yours a couple bays down, when I picked up mine Saturday.
Have you have issues with the TPMS, like I have?

I had a chance to talk with the one service adviser that seems to treat me well. He offered to just sell me the antenna and if I need to have it programmed, he'd take care of it, since it's only a couple of minutes to do.

He also said if it was the wheel sensors, he'd cover those since it's only 2 weeks past warranty. So, there is progress. I am going to replace the antenna unit, and commence to reverse engineer the old one. Hopefully, I will get some useful service information for others who are burned by this inferior component. Maybe to the point of being able to repair, or find a more robust replacement.

 

[DeedWest]

It was by the door! Had to snap a photo...I like the matching colored license plate as well. Soft top was halfway rolled off, so I'm assuming they were working on cabin blower. At the exact moment I was there, it looked like they were finally road testing #134? (arctic white 1.5 from Oklahoma) after two battery replacements.

I've only seen the TPMS issue come up once in my current Roadster. Driven over 800 miles so far. My previous 2.5, #1213 had it show up three times within the time I owned it, & I drove 10,300 miles roughly. That's definitely progress. The guys I usually deal with have always taken great care of me, but then again, I haven't had any too frustrating problems yet, other than my 400V controller failing a day after taking delivery of my current Roadster.

I'd definitely be interested in a more robust component, and I'm sure others would be too. Keep us updated on what you discover!

 

[candersoh]

I'm kind of late to the thread, but it's worth mentioning that you aren't the only one with this recurring problem. I've been through at least 4 replacements of the TPMS if not more. Currently have the "TPMS Hardware Error", but am waiting for next years service to do something about it. Roadster #619...
//dan.

i can also be counted to the list. 2011 2.5S. this will be my third TPMS...

 

[scotty2541]

I've been silent... but not bored. Here is a summary:
That TPMS issue, summarized