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Anyone ever swap VMS modules?

ElectricLove

Member
May 28, 2013
551
312
I'm wondering if anyone has replaced their VMS modules, on their own...

What I'm trying to get at is whether the VMS module is what determines the VIN/model/Firmware of the vehicle or if that is somewhere else? I would think the VIN and whether it is sport or "regular" would be in either the VMS or the PEM. So far nothing really sticks out in the PEM. We are comparing a 2.0 sport with 2.5 non-sport...
 

ML Auto

Member
Mar 8, 2014
716
719
SW Florida
If you swap the VMS take out the gauge cluster. I swapped gauges once and the mileage got reprogrammed to the higher mileage reading. Swapping them back gave me a mileage mismatch error, and it would not correct back to the original lower mileage. Now I have to see if driving the car for 1500 miles with the cluster disconnected will equal out the two readings and clear the code.
 

ElectricLove

Member
May 28, 2013
551
312
If you swap the VMS take out the gauge cluster. I swapped gauges once and the mileage got reprogrammed to the higher mileage reading. Swapping them back gave me a mileage mismatch error, and it would not correct back to the original lower mileage. Now I have to see if driving the car for 1500 miles with the cluster disconnected will equal out the two readings and clear the code.

Yikes, that is crazy... So if you swap both the gauge cluster and the VMS, theoretically the mileage would match and the vehicle would now report lower mileage than reality? That is interesting, I wonder what happens if we swap both then, would we have effectively "tricked" the car into thinking it is the VIN/ID of the vehicle from which the VMS is being donated?

Will the car turn on and drive without a gauge cluster connected?
 

supersnoop

Tesla Roadster #334
Mar 24, 2014
1,111
221
Pflugerville
Most cars (at least the ones I'm familiar with) store the mileage in two separate modules and compare the mileage against each other at start up. If there's a different, the odometer tamper light comes on and you can never sell the car as "actual miles" again. The VIN is sometimes validated separately from a third module.

If you replaced both modules from the same donor vehicle, there's a chance that the donor vehicle's mileage would show up, and it may or may not be flagged as invalid.

Generally speaking, and with my experience with other makes, the dealer/service center will have tools to replace either module with brand new module and maintain odometer accuracy. Only the factory could (maybe) have the tools necessary to correct the mileage on a used module. Otherwise, you're looking at flashing and soldering eeproms.

There is usually some flexibility in the stored mileage; if the two modules are off by 5-15 miles, the higher is written to both modules. So, if you screw up and the tamper dot shows ups, don't drive it more than a couple miles, and swap everything back.
 

ML Auto

Member
Mar 8, 2014
716
719
SW Florida
Will the car turn on and drive without a gauge cluster connected?

Yes, with some errors popping up.

I haven't found any other modules that might record the mileage or VIN, so I am pretty sure if you swapped the VMS and cluster, the car wouldn't know the difference. That would only be useful for testing purposes.
 

BartJ

early member
Dec 13, 2014
537
293
Belgium
Let's give the guy a break. I think he is trying to learn hout to repair Roadsters and to offer options like a lighter battery.

Ok sorry.
But I doubt it really that someone will ever be able to offer other battery packs without the co-operations of Tesla.
you will need access to the source code of the software in any case.
 

ElectricLove

Member
May 28, 2013
551
312
What are you guys trying to achieve here ???
VIN fraud , mileage fraud, can't think of anything else...

Definitely not either of these!

We are learning the ins and outs of the roadster to offer repair and upgrade options... Need to understand what components are doing what and how and when so we can understand what goes wrong and how and when and what can't be mismatched, etc...

- - - Updated - - -

Just an data point, I unplugged the ESS and PEM, here is what it looks like when you boot up the VMS --> Roadster - YouTube

Based on this video I so badly want to go do a VMS swap, with gauge cluster uninstalled and see if the screen is going to then show the VIN/data from the new VMS, or if there will be a mismatch between VDS and VMS... I'd think worst case scenario is just swap them back but I'm very nervous about ruining the vehicle, of course this is the risk we take on doing what we are doing!

Any chance you have a video with only the VMS removed?
 
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Reactions: DanielFriederich

BartJ

early member
Dec 13, 2014
537
293
Belgium
Definitely not either of these!

We are learning the ins and outs of the roadster to offer repair and upgrade options... Need to understand what components are doing what and how and when so we can understand what goes wrong and how and when and what can't be mismatched, etc...

Ok I apologize.
 

ElectricLove

Member
May 28, 2013
551
312
Ok sorry.
But I doubt it really that someone will ever be able to offer other battery packs without the co-operations of Tesla.
you will need access to the source code of the software in any case.

We will see, rather than not try because it seems difficult I'd rather put in the effort and try to "do something cool for roadster owners"... I feel like I heard that line from someone else before, heehee!
 

supersnoop

Tesla Roadster #334
Mar 24, 2014
1,111
221
Pflugerville
On my BMW, almost every module had to be coded with the VIN or it wouldn't work, in some cases rendering everything on the same bus, or even the car inoperable. I would expect similar behavior from the Roadster.
 

ElectricLove

Member
May 28, 2013
551
312
BMW is a very old company with many many years of R&D put into every component of that vehicle.

Now the Model S I may agree with you but I think the Roadster is a very "basic" EV conversion of a Lotus, I don't think it has the level of sophistication... Maybe though...
 

ML Auto

Member
Mar 8, 2014
716
719
SW Florida
On my BMW, almost every module had to be coded with the VIN or it wouldn't work, in some cases rendering everything on the same bus, or even the car inoperable. I would expect similar behavior from the Roadster.


The big manufacturers code the VIN to make used parts useless and make more profit on overpriced new parts. Tesla got the overpriced new parts right but I don't think they coded any modules, as I have not run into any problems yet.

- - - Updated - - -

Ok sorry.
But I doubt it really that someone will ever be able to offer other battery packs without the co-operations of Tesla.
you will need access to the source code of the software in any case.

If you just replace the cells with ones with the same voltage, you shouldn't need to do anything else. The only output from the bricks are voltage and temp. Everything else is just a calculation. The 3.0 battery seems to require a different voltage for charging, hence the PEM upgrade.
 

ElectricLove

Member
May 28, 2013
551
312
We have successfully transplanted a 2.0 Sport PEM into a 2.5 Non-sport Roadster... It can be done with only minor modifications necessary...
 

supersnoop

Tesla Roadster #334
Mar 24, 2014
1,111
221
Pflugerville
If you just replace the cells with ones with the same voltage, you shouldn't need to do anything else. The only output from the bricks are voltage and temp. Everything else is just a calculation. The 3.0 battery seems to require a different voltage for charging, hence the PEM upgrade.
Are you sure about the different charging voltage for the 3.0? Doesn't the 1.5 use the motor to charge, not the PEM? I can't imagine how they overcame that.
 

ML Auto

Member
Mar 8, 2014
716
719
SW Florida
Are you sure about the different charging voltage for the 3.0? Doesn't the 1.5 use the motor to charge, not the PEM? I can't imagine how they overcame that.

The motor coils are incorporated into the charging system in the 1.5, but the electronics are in the PEM. I believe that is why is 3.0 battery was delayed for the 1.5 models. The charging system required a different upgrade for the PEM.
 

hallvardr

Member
Sep 17, 2016
126
97
Norway
I'm wondering if anyone has replaced their VMS modules, on their own...

What I'm trying to get at is whether the VMS module is what determines the VIN/model/Firmware of the vehicle or if that is somewhere else? I would think the VIN and whether it is sport or "regular" would be in either the VMS or the PEM. So far nothing really sticks out in the PEM. We are comparing a 2.0 sport with 2.5 non-sport...

Did you ever get to try this?
 

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