Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Faults: HVAC cable fault; ESS Cable Interlock fault; Vess too low during precharge, t2

This site may earn commission on affiliate links.
Many thanks for sharing @wiztecy! First, really great to see a breakdown of the 400V controller regardless of the fault. The one terminal of R4 looks horrendous as you noted. Did you get a chance to pull the bottom PCB to see what the underneath of the board looked like? Maybe the solder contact trace is shot underneath although the resistor itself is fine (at least with no V going across it).

Re the connection with water intrusion.The box seems well designed (minus a gasket). I doubt it could get enough water in there to reach the underneath of the board, but I guess anything is possible. As you note, the bottom PCB was not encapsulated. I often wonder about effects of severe condensation though. I've seen warm blasts of air come into my barn to make it rain off of cold metal surfaces.
 
The one terminal of R4 looks horrendous as you noted. Did you get a chance to pull the bottom PCB to see what the underneath of the board looked like? Maybe the solder contact trace is shot underneath although the resistor itself is fine (at least with no V going across it).

Re the connection with water intrusion.The box seems well designed (minus a gasket). I doubt it could get enough water in there to reach the underneath of the board, but I guess anything is possible. As you note, the bottom PCB was not encapsulated. I often wonder about effects of severe condensation though. I've seen warm blasts of air come into my barn to make it rain off of cold metal surfaces.

I did pull the lower PCB out, had to do that to tighten down the loose HV+ line and also to inspect that R4 solder point. The solder point on the lower portion of the PCB looked fine. All of the solder points and lines look good as well. Interesting enough the bottom of the lower PCB board is coated in conformal coating, however the top is not from what I can tell. Meaning all the chips and lines are exposed and no moisture preventative coating applied to them or the top of the PCB.

I feel what created this failure was loose HV+ terminal lug in the control box.

Next step will be to test the four capacitors and diodes. Also to try and follow the flow and test each start / end point to ensure the traces are good.

The 1.5 control box is built pretty solid. But we are reaching a point where some of these gaskets begin deteriorating as well as their their sealing ability. Once I get things up and running again I'm going to put some silicone grease along these gaskets on the controller and top PEM cover. I also found out that those PEM screws that hold down the PEM cover have no water proofing from what I could tell. Its a torx scew type with a flat / beveled washer. But no o-ring for any type of seal. I may add an o-ring to between the top of the PEM and the bottom of this flat washer to aid in preventing water from creeping in.
 
At least its good to know the bottom of the board is coated on your 1.5 lower PCB. If the traces/solder are good, then that is a good sign. Hopefully your systematic isolation of components IDs the remaining fault.

I went to check my 2.0 controller box when you first mentioned your recent issue. On 2.x the gaskets are on both vertical ends. The exposed portions of the gasket are still nicely pliable, but the position is not comforting as the gasket has an edge that faces up on each side (good spot for water intrusion if indeed that is an issue). As with most of the items on the roadster, I would like to retorque to spec., but I don't know what that spec is. So I will probably use best judgement and make sure all is snug.

Thanks for sharing your journey with your 440v box.
 
So today I checked the fuse block by the passenger side that's inside the cabin, all fuses appear to be good. In doing this I found one of my yellow shop rags tucked up into the under dash area by the foot-well, by the VMS box. I pulled it out and its chewed up as well as rat droppings fell out. Damn it. So now I need to pull the dash apart to see if there's any chewed wires, another variable in this mix. One thing is that it appears if you have full comprehensive auto insurance that it may cover these cases of rats chewing on wires.

Well I may dig into the dash this or next weekend.....
 
Do you think you left the rag up there or did the varmint drag it up there?

The rat took it up there. It has chew holes in it plus it chewed on my CD case. My friend said these varmints like to sit in places that are warm at night, so my Roadster was parked in the front of the house where its sunny during the day. It holds the heat though the night so these creatures try to find a warm place to stay typically and hole up in there.
 
Just what you need at this time... hopefully you have another under dash project which makes the tear down beneficial. I found a really old (no odor) mouse or chipmunk nest located in my dash just in front of the instrument cluster. A few tiny nibbles , nothing major but a nest. I put a hard plastic spiral wire loom around most of the wire looms in case it returns. A few in the forum have had mice. Some very expensive posts also where the loom needed replacement. Hopefully yours is a mild tenant like most.

I have only seen one scientifically proven way to prevent mice from entering a car. Unfortunately, it consists of a 10-12" high sheet of aluminum (or similar polished surface) flashing positioned vertically wrapping around the perimeter of the car. Mice cannot climb the flashing. Some swear by Cab-fresh over peppermint oil, dryer sheets, etc as a solution, I've never seen any controlled studies on these.
Thankfully, I don't think the tesla has wire insulation that contains soy which was a disaster for a number of car manufacturers a few years ago. I believe Toyota even developed a tape with capsaicin to wrap their wires to prevent mice at dealerships. Be safe, don't forget your respirator when you clean.
 
  • Informative
Reactions: wiztecy
The rat took it up there. It has chew holes in it plus it chewed on my CD case. My friend said these varmints like to sit in places that are warm at night, so my Roadster was parked in the front of the house where its sunny during the day. It holds the heat though the night so these creatures try to find a warm place to stay typically and hole up in there.
Maybe add some cats to your menagerie! ;)
 
  • Like
Reactions: wiztecy
For reference purposes only as previously discussed here :eek:

3510303757_fdfccd49cb_b.jpg
 
  • Informative
Reactions: dhrivnak
Great post, wiztecy - your knowledge (and fearlessness!) is awesome!
But here i am - same problem as you have had. 2010 Roadster Sport 2.5 - lives in Florida - i am in Toronto in the summer. Came down in summer, having only been gone a month, to discover it completely bricked, tho charger was on and connected - zero miles, and would not charge. Tesla towed, and in the end, they covered it - and new battery! Got it back 6 weeks later, drove it literally 40 miles,.and DEAD on side of road - !!! - the same errors you discussed (which I didn’t get to see the first time). They towed again, got it back a few weeks later, and it seemed fine. Went back to Toronto, having left a Nest camera sitting on the Center-console, focused on the screen so i could see it charging and SOC at any time, just in case - all good. Came down 2 weeks ago, for the winter - been happily driving it for past 2 weeks - nothing crazy, no maniac, pumping it here and there for fun (of course), but never even broke 75mph. Have maybe put 400 miles on max, in the 2 weeks - no sharp bumps or upset, no rain, hadn’t even washed it yet (but was ABOUT to!), etc (all the possible things that i see you discussed) - and i’ll be danged if it didn’t die AGAIN! Exact same. Thankfully 500yds from my door - was doing like 25mph (gated community), and had just driven maybe 40-50 miles total. As you know, it just is dead - the only way to recover at all is to stop completely (since its coasting still when it dies), key off, wait a minute, key back on, and hopefully continue - limping with no power - maybe goes 8 feet, maybe goes 100 yards. Got back to the house, called Tesla, and waved goodbye to it for THIRD time since July ... (having not even put 1000 miles on it total!)(i am in toronto all summer, with brief monthly check-in visits)
ANY idea what this is? Or how to solve or what is causing?? What did Tesla fix the first and second times, that is now buggered AGAIN? And HOW?
Thanks for all your amazing research and posts!
 
Dear friends,
After driving 40 miles on a hot summer day (no moisture), we received the following error message:
“DMC HW: ESS Cable Interlock fault”
The car died on the side of the road and we had it towed to the Service Center.

After a week, they said it was just a loose cable, maybe they disconnected it when you had the stereo installed. I said the stereo was installed 2 years and 20,000 miles ago, and 2 it’s been through 2 annual services. I also asked if they saw evidence that the stereo installers hooked anything up down there because they were expressly forbidden from connecting to anything other than the 12v. They said no, it was a pro job. Maybe, they said, I hit a bump and it came loose. I don’t think so, but whatever if they said the car is fixed, let me get it out of there and get it home for cleaning (see below).

The car is missing a mudflap on the driver side that was supposed to have been replaced by Tesla. The service manager then ran his hand on the inside of the wheel well and received an electrical shock. They dismissed that as a total fluke, maybe just a little static electricity, and then reassured me that this problem is not related and it’s all good. We drove it home from the service center and the same damn error message popped up and, luckily, the car died on my street allowing it to coast it into the driveway before it died again.

Now as an aside, my beautiful car that is hand detailed by me and kept in the garage went to the service center immaculate and came back covered with thick dirt, leaves, and baked on birdshit EVERYWHERE. It was actually unimaginably filthy. I even happen to have before (from the tow truck) and after pics with the mess. Not wanting the crap to bake on any longer, I washed the dead car. Before trying to push it into the garage I decided to give it one more try and it started right up without errors.

Obviously the service center doesn’t know what’s going on and they do not treat the cars well while in their care. Any thoughts as to what this could be would be greatly appreciated.
 
The cable interlock is a loop going thru all the orange high voltage connectors to verify they are connected and safe from HV leakage. If any one of them becomes unplugged, the car will shut down. I would turn the car on the wiggle all the HV connectors and cables to see if you can get it to fault. The interlock circuit is low voltage so you won't get zapped. Connectors are at the PEM, ESS, A/C controller under the hood, and battery heater in front the right rear tire.
 
  • Informative
Reactions: hcsharp
It sounds like an intermittent connection at one of the components. With a low voltage/current circuit you can have intermittent contact without burning up anything, so you need to wiggle and move things around until you find where the fault is. Heat or vibration can move things around, making or breaking contact.