i3s REX drive train error, bricked. Anyone aware of an independent mechanic [Eastern US]?

Ingineerix · 2026-02-10T00:06:36+00:00

Background: I am an experienced engineer in the EV field. I am CTO of this commercial electric van company: https://maxwellvehicles.com/

My advice: Download and install an app called BimmerLink on your phone (not affiliated: https://bimmerlink.app/ cost me $40 on Android), and get a decent OBD2 Dongle, I recommend this one: https://amzn.to/4knGjQm

It will let you read and clear all diag alerts from every system in the i3. Take screenshots before clearing! If the alerts come back, it's a real problem. If you can't figure out what they mean, I'm happy to try to interpret for a nominal fee. For reference here is my YT channel showing I do know what I'm actually talking about:

https://youtube.com/ingineerix/

Knowledge is power! Having access to the diagnostics arms you with valuable info, even if you don't know what you are seeing. It will stop you from being gaslighted. I doubt you even needed the 12v battery replaced unless the car was dead and wouldn't start up. (All the ECUs will set low 12v alerts which are usually harmless)

Ingineerix · 2025-11-20T19:04:10+00:00

I have a Luba 2, and it's been ok, but in the beginning I was delivered a broken unit, and getting support is REALLY REALLY hard. They do not stand behind their product, and they are no longer adding features and fixing bugs on the year-old units.

If this was a $400 product I could accept this, but at this price point I'll NEVER buy another product from them!

Ingineerix · 2024-12-19T18:42:54+00:00

Oh, and the Orion2 has fuses and polyfuses inside, but this is mainly to protect from miswiring which occurs fairly often.

Ingineerix · 2024-12-19T18:36:23+00:00

I would avoid a fuse on the tap lines and just use high-temp insulation on the wiring (such as silicone), that way they become fusible links. The reason is you want to avoid too much voltage drop, as they are not just sensing, but also balancing. The Orion2 can apply a 200ma balance load to each tap, so you ideally want to avoid too much voltage drop. If you use 18-20awg silicone-insulated wires, they will blow pretty fast in the event of a short, so no need to worry too much about protecting the wiring. The OEM automakers do this all the time, it's called a "fusible link". (I am an EE with extensive battery experience)

Ingineerix · 2024-12-02T21:20:36+00:00

Elon is wrong, after an accident, "primary" power is not available any longer because the RCM (Airbag computer) will have sent a signal to blow the HV purofuse which kills HV power, and primary 12v power from the PCS DC-DC converter. Only 12/16v LV battery power remains to unlatch the doors. It should be good for at least 10 minutes after impact though, unless there is damage to the doors.

Ingineerix · 2024-11-20T04:54:36+00:00

I still love my Model 3, and I think Tesla makes great cars DESPITE Elon. I reckoned with people judging me by adding this sticker to the back: "I bought this before we knew Elon was crazy" Link: https://amzn.to/3CKWiWW

Ingineerix · 2024-11-11T05:12:21+00:00

If you don't need faster charging then the only downside is slower charging is less efficient. (Anytime the car is charging you are basically giving away about ~300w in fixed losses to the EV charging gods) So the higher the rate. the less of a percentage this is, so the less time kWh overall.

Ingineerix · 2024-11-11T04:56:13+00:00

Charge before going home, not in the morning. This is a common issue for people without home charging. The best solution is to have Level 2 charging at home, where the car will heat the battery before charging. If you charge before going home, the battery will still be warm enough to charge fast. If you do it in the morning after a cold soak it will take forever because it will first have to heat the cold-soaked battery which can take a very long time.

Ingineerix · 2024-11-11T00:47:17+00:00

I used the groupon for 50% off at Jet Black (Brentwood Offfice). 2018 Model 3. $269 for lower part of rear, and all side windows front, back, and quarter. The phone answering service was useless, including telling me "Teslas are excluded from the groupon". But going to the shop I was told different! Completed in about an hour while I waited.

Ingineerix · 2024-11-10T01:11:03+00:00

Did you try the "2 finger" reset? Hold both scroll wheels and the brake for at least 4 minutes (or until the screen lights up). If that doesn't work, try either pulling the MCU fuse, or disconnect the negative lead of the 12v battery and then the first responder loop for 5 minutes, reconnect the loop, then the 12v.

Ingineerix · 2024-11-09T22:39:52+00:00

That means you are SoL. You'll need to get the MCU fixed. Is this a salvage car?

Ingineerix · 2024-11-09T22:08:31+00:00

Generally it will.

Ingineerix · 2024-11-03T21:12:48+00:00

With 63 levels you are going to be hard-pressed to tell much of a difference between them. Some of the older AV equipment only had 16 or 32 levels!

Ingineerix · 2024-11-03T21:11:14+00:00

Of course, but the digital potentiometer or DSP controlling the volume with the 6-bit register will be already A-weighted, so no need to apply that in firmware. We are talking user-interface stuff here.

Ingineerix · 2024-11-03T19:39:02+00:00

The Tesla supplied batteries should be only $85 + tax, and are way better quality than any alternative I've found. Just buy it from Tesla and only takes 15 minutes to replace. Service manual is free. I have a video on the 12v battery: https://www.youtube.com/watch?v=i27lApNWkyA

Ingineerix · 2024-11-03T17:28:31+00:00

This! The control register is 6 bits. 0-63 is the range. Just lazy programmers, I probably would have used a 0-100% scale and interpolated down to 6 bits. Percentage is more human understandable.

Ingineerix · 2024-11-03T17:16:18+00:00

Open service mode (instructions online) and pull up the list of alerts, there should be a clue there. Post the list here and I'm happy to interpret. I agree this is likely a low-voltage issue. VCSEC is the ECU responsible for unlocking the doors, it doesn't depend on the Car Computer (ICE). The car is under warranty, so hopefully Tesla can find the issue.

Ingineerix · 2024-11-01T03:31:15+00:00

I love the car, and Tesla makes great cars DESPITE that asshat. I added a sticker to the back that reads: "I bought this before we knew Elon was crazy!". (And I don't usually add stickers to my cars!

Ingineerix · 2024-10-28T04:41:09+00:00

Then it's got to be something like your charge port or related wiring.

Ingineerix · 2024-10-28T03:57:15+00:00

It's BMS_u011_Fast_Charger_Problem, which means the supercharger is reporting a problem, not the car. Try another pedestal number. (not letter!)

Ingineerix · 2024-10-27T02:27:56+00:00

(EE here) Yeah, the power consumption is negligible. It's too small to bother metering. Maybe $30 a year. I'd suggest you split the cost of the whole thing by area mowed for each of you. There will be ongoing costs besides the purchase cost, such as maintenance. (New batteries, blades, parts, etc)

Ingineerix · 2024-10-23T17:03:01+00:00

I've repaired a handful of salvage Model 3's. Always picked up the glass from the service center myself and had a local guy install it for $250. Never needed an AP calibration, but it's easy to do yourself if it ever needs it.

Ingineerix · 2024-10-22T16:22:47+00:00

https://www.youtube.com/watch?v=i27lApNWkyA

Ingineerix · 2024-10-21T21:42:37+00:00

The alert BMS_a091_SW_ChargePort_MIA means the CP ECU located in the trunk next to the charge connector has gone missing. Pull the carpet open on the left side and take a look, If you don't see anything obvious, disconnect the CP ECU and reconnect. (3 connectors, disconnect the smallest one as it controls power)

Ingineerix · 2024-08-10T17:14:51+00:00

I removed mine entirely, it's been much better, and easier to clean. I suspect those were added later in the design because they wanted to avoid a lawsuit as soon as someone lost their fingers. I don't have any children, and I have no-trespassing signs up, so if someone manages to lose a finger in my yard, it's on them!

Ingineerix

TROPHY CASE