Tesla Gen 3 charger board assembly as of mid-2024

[tom91]

You need to apply the DC HV at almost same time as EVSE activate, there is an output for this. OUT1 - HV enable

There is an output that is controlled by the software, it pulls to ground when it wants HV. The rest is up to you to figure out for your setup.

[RobCote]

Using out 1 to actuate the contactors just makes them sound very unhappy. It's like they're cycling open-closed-open-closed very rapidly - it just makes a buzzing sound. And doesn't charge.

[tom91]

... Are you precharging? Do you have any basic knowledge of HV safety and wiring, is the charger properly fused?

Also the output CANNOT control these contactors directly.

[tom91]

But my best guess is a temperature sensor? Anyway, didn't realize they were connected when I removed the modules, broke the leads. Not sure how to ID them to replace them, so kind of hoping they're not strictly necessary.

Is there a way to temporarily ignore temperature within the software if that's a potential roadblock, to see if that's the hangup? Then I can work on figuring out how to replace them if necessary.

You need to resolve this first.. Did you measure the resistance of the broken sensor? Did you remove one?

Or did you just simply solder everything back in except the bits you broke and are now hoping for the best?

[RobCote]

Do you have any basic knowledge of HV safety and wiring,

Nope, not really!

did you just simply solder everything back in except the bits you broke and are now hoping for the best?

BINGO!

[RobCote]

Is there a precharger inside the battery pack? It doesn't really seem like not precharging would prevent the charger working, in any case, so I don't think that's the root cause.

[RobCote]

I could use some more help. I posted this elsewhere a few weeks ago but haven't got any response. Maybe if I provide a bit more info we can get somewhere.

This is the broken component on the module board:





It's identified as J2 on the board:



Tom asked for resistance of the component a while back - I've only just got the module off again - I measure an open circuit across the two leads. I'm going to attempt to extract it to try to get more information. The yellow epoxy is hard, so it'll probably be a struggle but I'll see what I can find.

[RobCote]

It's bonded to this ceramic plate:



Unfortunately, it seems the blue coating which may have had any markings was adhered to the epoxy stronger than what's underneath it, so it mostly lifted off as I extracted it:





I'm not super familiar with small electronics. How do I ID this component?

[RobCote]

I just soldered the broken leg back on. Seems like an easier solution than trying to ID the capacitor. My multimeter didn't seem to give a consistent reading, and I'm not sure how I could possibly determine the material. So, yeah. See what happens I guess.

[RobCote]

No change.

What am I doing wrong here?

[tom91]

You still have not managed to get any CAN info from the modules have you? I would start there first.

Have auto refresh on and plot some of the modules values and try waking them up to see if they change. choose a value like temperatures so you do not need to have HV or AC attached.

[RobCote]

I haven't read any can messages since early hexcan VAG-COM days, and that was pretty dummy proof. What additional hardware do I need to read can info from the open inverter board?

[tom91]

The spot values relating to each phase will populate.

Can you post pictures of your wiring to the charger modules? Possibly you did not wire the CAN correctly as it should be a twisted pair.

[RobCote]

Forgive me that it's a little bit ugly right now. I used orange and orange/white twisted pair to CANL and CANH on the first module, then piggy-backed off that to the second module with individual wires not a twisted pair. Is that wrong?



Hopefully these pictures get the point across, it's hard to tell what you're looking at.

[tom91]

Yes twisted always for CAN.

Is the OEM board not removed in the front? Did you just remove module connector?

It is key to get the CAN communication working first or proven out first.

[RobCote]

I de-soldered the headers from the OEM board to disconnect it from the modules. I was worried about wedging in an insulator like Damien did potentially falling out while driving.

I'll redo the module-to-module jumpers with a twisted pair and put a 120Ohm resistor across the terminals tomorrow and see if that changes anything. I appreciate your input on this because it's been a real head-scratcher for me.

[RobCote]

I soldered R120 across the terminals of the module furthest from the control board. I twisted the pair of wires that jumper the two modules together. With the module board unplugged from the modules, I measure 120.0 Ohms across the CANL and CANH terminals in the 12-pin connector. That tells me the solder joints are making connection, the resistor is resisting as it should, and there's no short across any of the can terminals. They're small, so it's tough to see.

With AC and HVAC disconnected, I plotted all 9 temperatures (l and r, though I'm not sure what that indicates?) and nothing showed:



One thing I'm not clear on is whether I need to solder termination resistor(s) onto the OI board? There are two locations labeled "solder for ext can", that I've not done anything with. I THINK it allows the control board to communicate with components other than the charger, but like I said I'm not quite clear. But I wanted to share that I've not put a resistor there, in case that's relevant.

[tom91]

If you measure the controller board side what resistance on CAN without it powered what is it?

Did you get the LEDs on the modules, as they need to be woken to communicate?

Solder jumpers not needed as that is for the external connection and not to the modules.

[RobCote]

If you measure the controller board side what resistance on CAN without it powered what is it?

120 ohms.

Did you get the LEDs on the modules, as they need to be woken to communicate?

Yes. They always come on as soon as the control board is powered on.

Solder jumpers not needed as that is for the external connection and not to the modules.

Noted.

[tom91]

I guess your charger is dead or something else is weird. Have you double check your CAN L is CAN L on all connections?

Next step I would do is get something to read CAN and look at the CAN activity to see if anything is actually happening.

[RobCote]

I triple checked my connections. But just to be explicitly clear I have it right:

Pin 5 (looking at the OI board with the text printed on the board in the correct orientation (i.e - CONN 3 is top right)) is the second pin down in the left row and is CANH, and connects to the module boards at the 6th pin from the left.

I'm realizing as I type this that I may have misinterpreted CANL and CANH. Can you clarify for me - do I connect control board CANH to module board CANH, or to CANL at the module?

[tom91]

CAN H goes to CAN H, its a bus not a device to device (Master to Slave) as in its a multi device bus so tie all the same signals together.

Please annotate a picture for me.

[RobCote]

Is this what you wanted to see for annotations?

[RobCote]

Next step I would do is get something to read CAN and look at the CAN activity to see if anything is actually happening.

I'd like to understand this a bit better. What would I need to do it? What might I learn? If there's no traffic on the bus, then there's no traffic, even if I read it with a different device. Right?

[tom91]

I'd like to understand this a bit better. What would I need to do it? What might I learn? If there's no traffic on the bus, then there's no traffic, even if I read it with a different device. Right?

Yes but the controller sends traffic so you will know it reaches the modules. If there are no IDs that are expected from the charger modules it means they are dead.

You need a CAN to USB adapter.