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2021 XC40 P8 White, we named her "Zippy" - v1.8
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Discussion Starter · #1 · (Edited)
See Post #25 - Definitive location of TCAM backup battery (BUB)?
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Does any know where the TCAM BUB is and how to access it?

I've combed through every thread on here, and everyone points to the PoleStar thread, which is not the same for the XC40. Or they just say it "should" be in the cargo roof area under the TCAM sharkfin antenna. But no confirmation anyone has actually seen it.

Please, if you know, be specific.
 

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2021 XC40 P8 White, we named her "Zippy" - v1.8
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Discussion Starter · #3 ·
Do you know the steps to access it in order to reset the TCAM by unhooking the BUB?

I found the tech update where they show how to remove and reseal the shark fin. The pics show a wire going into the roof, but I couldn't see a battery in the TCAM itself.

So I assume one would have to find a away to remove the interior fabric? I felt around through the fabric and didn't feel anything up there.
 

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Discussion Starter · #5 ·
i want to say its in or around the c pillar - i remember (vaguely) seeing a schematic somewhere
Nope... Ur thinking about the PoleStar, which people keep referring to.

This is the XC40. As far as I can tell, no one has actually seen or touched the TCAM BUB in an XC40.

Anyone else?
 

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2022 XC40 Recharge Twin Fusion Red
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Nope... Ur thinking about the PoleStar, which people keep referring to.

This is the XC40. As far as I can tell, no one has actually seen or touched the TCAM BUB in an XC40.

Anyone else?
Yep pretty sure it is behind the LH rear quarter panel (“C pillar”) trim. It was shown in one of the docs that was shared on here for the XC40. Sorry can’t recall what doc it was - either one of the service bulletins on how to charge it, or the doc showing the TCAM functionality.
 

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The TCAM manual for the Volvo

Thanks for posting that again. Unfortunately as you showed the image appears to be the Polestar 2...however I’d assume the BUB is located in a similar position in the XC40??
 

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The descriptor states that this is the module used in the Volvo. The filing is for the FCC and the picture may not be
specific for the actual car. It is, I believe, a diagram that is meant to give basic information for any Volvo that has the component.

The other images in the document do appear to correspond to the Volvo.

However, I may be wrong...

This is the BUB from the PDF posted.

Rectangle Font Electronic component Box Computer component
 

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2021 XC40 P8 White, we named her "Zippy" - v1.8
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Discussion Starter · #12 ·
That's not an XC40 ;)

This TCAM manual does not show where the BUB is located, only that it exists as one of the sub components. And as I feared, everyone keeps recycling the same erroneous or inaccurate links and documents, or saying "pretty sure"/"I think"/"I read somewhere".

Note: In the Polestar Forums, there are clear instructions on how to access and reset the BUB, as there is an access panel to it in the "C Pillar" via a 7mm bolt. The XC40 does NOT have the same "C Pillar". In the XC40, there are access points to change the rear bulbs, but the BUB is NOT located there. So the BUB may be: 1.) in the actual TCAM outside the car, or 2.) directly under it inside the car between the roof and ceiling fabric, or 3.) somewhere completely different (IHU, Frunk, etc.). I've spent hours trying to find a way to look behind the fabric, but don't see any way get there without MAJOR disassembly of the trim and seals.

So back to my original specific question, has anyone actually seen/touched the TCAM BUB in an XC40 Recharge Pure?
 

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Discussion Starter · #13 ·
This is a little helpful, as if you drill down on some of the photos you can see the interface port on the bottom. Which infers the BUB would plug in there from a hole through the roof. And the other pics don't show the BUB as integrated into the TCAM antenna.
Font Rectangle Auto part Electronics accessory Transparency
 

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Discussion Starter · #14 ·
This is a little helpful, as if you drill down on some of the photos you can see the interface port on the bottom. Which infers the BUB would plug in there from a hole through the roof. And the other pics don't show the BUB as integrated into the TCAM antenna.
Well... I may have spoke too soon... just found this, which seems to infer the BUB is integrated into the base of the TCAM. Which would be counter to other documents and how Polestar does it.
32319770 - Battery. VCM, Module, Connectivity - Genuine Volvo Part
White Font Line Art Parallel
 

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This might explain why after 5 days at the Volvo workshop, apparently following instructions from Volvo Switzerland, they could not get mine back to life and ordered a new TCAM unit. With no delivery date...
 

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Discussion Starter · #16 ·
This might explain why after 5 days at the Volvo workshop, apparently following instructions from Volvo Switzerland, they could not get mine back to life and ordered a new TCAM unit. With no delivery date...
If you can, ask them specifically where the BUB is. If the BUB really is in the base of the TCAM, then there is no DIY way to reset it without risking voiding the warranty and/or getting in over your head.

I've tried almost everything else... all the button pushing sequences, resetting the network in the IHU menu, letting the car go into deep sleep, disconnecting the 12V battery and pulling the HV battery breaker for 10 mins, called VOD from inside the car ... all nada. The only thing I haven't tried is a factory reset via the IHU because some people report that the TCAM mysteriously comes back to life after sitting idle for days. So now I wait for an appointment in 3 weeks with no LTE/WiFi/BT networking, GPS, VOD app, fast charging, etc. But I may try a factory reset before then.

Unless there is someone else out there who can confirm the BUB is somewhere I haven't looked.

PS: if you are willing, let us all here know your outcome.🙏
 

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Hi,

I don’t know where the BUB is, but I think that I successfully reset my TCAM by pulling the 5 amp fuse to it in the fuse box in the floor panel under the glove compartment. I described the effort in this post:


good luck!


If you can, ask them specifically where the BUB is. If the BUB really is in the base of the TCAM, then there is no DIY way to reset it without risking voiding the warranty and/or getting in over your head.

I've tried almost everything else... all the button pushing sequences, resetting the network in the IHU menu, letting the car go into deep sleep, disconnecting the 12V battery and pulling the HV battery breaker for 10 mins, called VOD from inside the car ... all nada. The only thing I haven't tried is a factory reset via the IHU because some people report that the TCAM mysteriously comes back to life after sitting idle for days. So now I wait for an appointment in 3 weeks with no LTE/WiFi/BT networking, GPS, VOD app, fast charging, etc. But I may try a factory reset before then.

Unless there is someone else out there who can confirm the BUB is somewhere I haven't looked.

PS: if you are willing, let us all here know your outcome.🙏
 

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Discussion Starter · #18 ·
Hi,

I don’t know where the BUB is, but I think that I successfully reset my TCAM by pulling the 5 amp fuse to it in the fuse box in the floor panel under the glove compartment. I described the effort in this post:


good luck!
Thanks... but tried that as well as disconnecting the entire 12V battery. No Bueno...

Let's hope a unicorn passes by this forum and knows where the BUB is.
 

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Thanks... but tried that as well as disconnecting the entire 12V battery. No Bueno...

Let's hope a unicorn passes by this forum and knows where the BUB is.
You could always remove the C-pillar trim and look for it. IIRC there was instructions for installation of the illuminated rear sill plate trim posted here and it showed how to remove all the trim as it was necessary for accessing the wire harness.
 

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Apologies for the tangential post, but thought I could share. Whilst I was struggling with my own "no lte, no GPS, charging greyed out to 6amps, no wi-fi, TCAM reboot does not work," issues. I discovered the TCAM is covered by its own fuse. (At the time I had not heard of the BUB). I removed the fuse, counted to thirty and replaced it. Of course it made no difference for me unlike for @afung . I'm following this thread in the hope someone finds the BUB in the XC40 for next time, but in the meantime it occurred to me that if we pull the TCAM fuse and leave it out, the BUB must eventually drain down.

There will need to be some experimentation to find out how long the BUB lasts, but it should ultimately reset the TCAM once drained. If someone who is currently stuck wants to try this, you are shooting for fuse 23 under the passenger footwell carpet. I can't find any information on what capacity the battery is but the Continental docs list the consumption as "Typical standby current: 3.5 mA dc (at 12 V) , Typical active current consumption: 350 mA dc (at 12 V) (cellular, Wi-Fi, BLE, GNSS active) ". My TCAM burst back into life after a week on its own, so maybe it can last a week at 3.5 mA? If so, this might be more painful to live with for some than the original problem as it will kill phone integration and so forth.

 

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