Tesla Gen 3 charger board assembly as of mid-2024

[RobCote]

Parallel connection and R120 on/off make no difference. I still get the same message on repeat.

[uhi22]

Most of the lines have a delta T of 0.0003s

This is 0.3ms, so clearly not the transmission cycle of the software, but a full bus due to missing ACK from other nodes.

[tom91]

So the charge modules are not functioning on the CAN bus.

Try connecting up the other one and see if anything changes. If not you need a new charger.

[uhi22]

Maybe check whether the CAN transceivers on the modules have connection to CANH and CANL, and whether they have supply.

[RobCote]

Maybe check whether the CAN transceivers on the modules have connection to CANH and CANL, and whether they have supply.

Do you mean continuity of the CAN and power wires to the control board? If so, yes, I've checked a few times. If there's a different check I should perform, please let me know.

[RobCote]

So the charge modules are not functioning on the CAN bus.

Try connecting up the other one and see if anything changes. If not you need a new charger.

Give me a few days to repair the broken cap and put it all back together and test.

[RobCote]

https://github.com/jsphuebner/stm32-teslacharger

The code that should be on your V5 board, it should always send the can messages I listed above. No real reason it should not be sending them, specially if you see just one.

How can I check this? None of the files at that link are .bin, which I believe it should be, based on the uart update instructions on the web interface. There's an option to upload new, but no way that I see to pull the existing firmware from the board.

[royhen99]

VER 1.19.R

[RobCote]

Thanks! I see version 1.17 R so I'll update it. Appreciate the link.

[RobCote]

Well the firmware update at least made a difference!! Progress is exciting. I see spot values populate on the web interface now:





However I still only see the one CAN message in cangaroo echoing over and over. Doesn't make sense to me. What do you guys make of that? Faulty USB adapter?

[tom91]

Nothing is showing, it just shows you how the CAN frames are populated for the messages form the modules.

No change on getting CAN working.

[RobCote]

Oh. You're right I see that now. Well at least I had a few minutes of excitement.

[RobCote]

Is there anything I can check on the module board to investigate why it's not communicating? I have to remove the other one to repair the broken capacitor tomorrow, so I'll have unfettered access to both sides. Any recommendations for what to look at are appreciated.

[uhi22]

Could you identify the CAN transceiver chip on the modules? It could be an 8pin IC, which should have CANH and CANL routed to it.

[RobCote]

I measure continuity from the open inverter board CANL and CANH terminals to this chip, as labeled:



I read these markings:
1040AQ
[Texas Instruments logo]83T
C0QYG4

I included measured voltages at each pin just for the sake of science. Of course, this was while the board was powered on. With power off, the middle two legs on the right hand side of U11 are continuous to ground (i.e. - the charger case).

As a side note, while I was probing things, I happened to touch the chip just to the right labeled U1 and noticed it was extremely hot. Is that normal? It heats up about 5s after I supply 12V to the board, and it didn't quite burn my finger, but it was more than simply warm.

Anyway, I was secretly concerned my solder joints may have been part of the issue, but I believe this rules that out. At least for the CAN connections.

[RobCote]

I put a 120Ohm resistor across the terminals at the module board. But I measure 62 ohms across those terminals, 42 ohms with the control board attached. That doesn't seem right?

[RobCote]

It's actually R164 and/or R165 that's heating up - just above U1 and partially obscured by my annotations. I measure about 130F with an IR thermometer. No HV or AC connected, just 12V. Is something fatally wounded here? Or is that normal? It seems odd.

[uhi22]

The CAN transceiver U11 is a TJA1040, and it's supply is OK. What is strange is the (average) voltage of the tx and rx line. If the board would not transmit anything (as your CAN log says), the tx line would be permanent high (5v). Any chance to record the tx and rx and CANH CANL with an oscilloscope? The RX should go to low as soon as CANH is significantly higher than CANL. The TX should at least shortly go to low at the end of a received frame (the ACK bit).

[RobCote]

I don't have a scope, unfortunately. Is there a cheap option?

[uhi22]

for just digital signals there are cheap saleae logic analyzer clones (below 10 Euros on aliexpress). For analog signals (and CANH / CANL are analog) I'm using owon VDS1022i two channel USB oscilloscope for around 80 euros. Would be good to know an alternative which has more analog channels, but the really good saleae with analog+digital capability (e.g. saleae logic 8) are much more expensive (>500 euros).

[RobCote]

A TJA1040 is $2. Does it make more sense to just try a replacement, rather than buy a scope first to prove it? Are you thinking the chip may be faulty?

Anyway, I did some testing and have a little more information I'm not sure what to do with. So the module board that I have been testing on is getting really hot in a pretty localized spot as I mentioned.

I swapped CAN wires over to the other module and powered it up to see what it would do with the new firmware. Same results with respect to communications - only one message on repeat. That same region of this module doesn't get any warmer than the rest of the board. I scanned the whole thing, actually, and there are no hot spots at all.

I connected power to the other board temporarily - but no CAN wires - and it got hot afternoon immediately.

Like I said - no clue what to make of it, but there it is.

[uhi22]

I do not think that the TJA1040 is broken, but maybe it is. I prefer to measure the things, this usually helps to find the root cause. If you see the chance to easily replace it you could give a try, but I guess the issue is somewhere else. Is the U1 connected to the tx and rx of the TJA1040? What type is U1?

[jrbe]

You might be able to use a "computer safe test light" to see communication pins flickering. It doesn't guarantee that the signal is good, just that there's at least a tiny amount of power or ground there.
Realize what makes the light safe also can make it seem like there's good power or ground as well but it will look about the same with a 10k or 50k resistor in line.

[RobCote]

I do not think that the TJA1040 is broken, but maybe it is. I prefer to measure the things, this usually helps to find the root cause. If you see the chance to easily replace it you could give a try, but I guess the issue is somewhere else. Is the U1 connected to the tx and rx of the TJA1040? What type is U1?

U11 and U1 have the following connections:

U11 top right (assuming pin 5?) is tied to the 4th pin on the left of U1. Bottom right of U11 (pin 8?) goes to U1 pin 5 (5th down left side). U1 pins 1, 7, 8 are ground when powered off.

U1 is marked:
Si8642ED
1817BFL0AG

[uhi22]

The pin 1 is usually marked with a dot, in best case on the PCB and on the IC housing.

The transceiver pinnings can be seen here: https://www.nxp.com/docs/en/data-sheet/TJA1040.pdf

The marking of U1 does not say anything to me, maybe a custom chip? But nevertheless, it should send ACK (and data messages) on the TX pin to U11, and it should receive the CAN messages from the U11 RX pin.
Just to make sure: You have ground of the module boards and of the control boards all conntected together? And all CANH together, and all CANL together. And you measure a resistance between CANH and CANL between 50ohms and 200ohms while everything is powered off? And you measure the identical resistance on the pin6 and 7 of all involved transceiver chips?