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Anyone ever swap VMS modules?

Discussion in 'Roadster' started by ElectricLove, Nov 17, 2015.

  1. ElectricLove

    ElectricLove Member

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    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...
     
  2. MLAUTO

    MLAUTO Member

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    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.
     
  3. ElectricLove

    ElectricLove Member

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    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?
     
  4. supersnoop

    supersnoop Tesla Roadster #334

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    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.
     
  5. MLAUTO

    MLAUTO Member

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    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.
     
  6. BartJ

    BartJ Member

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    What are you guys trying to achieve here ???
    VIN fraud , mileage fraud, can't think of anything else...
     
  7. dhrivnak

    dhrivnak Active Member

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    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.
     
  8. spaceballs

    spaceballs Member

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

    BartJ Member

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    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.
     
  10. ElectricLove

    ElectricLove Member

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    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 - - -

    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?
     
  11. BartJ

    BartJ Member

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    Ok I apologize.
     
  12. ElectricLove

    ElectricLove Member

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    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!
     
  13. supersnoop

    supersnoop Tesla Roadster #334

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    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.
     
  14. ElectricLove

    ElectricLove Member

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    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...
     
  15. MLAUTO

    MLAUTO Member

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    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 - - -

    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.
     
  16. ElectricLove

    ElectricLove Member

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    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...
     
  17. MLAUTO

    MLAUTO Member

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    What were your minor mods?
     
  18. supersnoop

    supersnoop Tesla Roadster #334

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    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.
     
  19. MLAUTO

    MLAUTO Member

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    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.
     

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