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Alert 972

Discussion in 'Roadster: Technical' started by Curt, Jun 4, 2017.

  1. gregd

    gregd Active Member

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    So, Tesla's infamous inconsistency at work...

    I was told a while ago that they can't open up a PEM in the service dept, so have to swap the whole unit. The service person said he thought it had something to do with it not being designed with proper ESD protections for that sort of work. So, that's why the whole PEM swap, in my case, to fix the PEM fan connector issue (burned contacts), which are on an easily swapped sub-assembly.

    If the whole PEM is swapped, then the whole PEM gets a warranty. If they only warrant the part that was changed, then they must have a way to open up the PEM for surgery. The time it takes for the 3.0 upgrade is not long enough for shipping the PEM back to the factory for the rework.
     
  2. slcasner

    slcasner Member

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    After my 3.0 upgrade I realized that I should have recorded the serial number or other identifying information on the PEM before taking the car in. It wasn't obviously different after the upgrade.
     
  3. Curt

    Curt Roadster Signature #55

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    Quick update...

    Five weeks and counting. The Service Center has had a replacement PEM for several weeks, but not the "3.0 Upgrade" board for the PEM. That board arrived early this week, and the PEM was replaced.

    Unfortunately, the car is now failing to take a firmware update.
     
  4. Curt

    Curt Roadster Signature #55

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    #24 Curt, Jul 15, 2017
    Last edited: Jul 15, 2017
    After six weeks, I got my Roadster back this morning!

    They ended up replacing the PEM and the VMS (wiping out my logs in the process). They also found a fault in the DMC board of the Reman PEM, and scavenged the DMC board from my original PEM. The good news is they judged that everything fell under the warranty from the "3.0" Battery Upgrade, so I feel pretty lucky about that.

    The only thing that bothers me is that they never identified where the fault was/is, so I'm not fully confident that it is fixed.

    I repeated the drive that caused the first set of failures, and had no problems. The temperature today is at least 5F degrees cooler than on 3 June, so I still can't say for sure.

    Interesting data point - starting with empty logs, new PEM, and new VMS: the CAC jumped from 208.75 to 215.04.
     
    • Like x 1
  5. wiztecy

    wiztecy Active Member

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    Thanks for the thread, very informative. And yes that jump is interesting in the 3.0 pack. Think it may be with the pack balancing? You haven't had your 3.0 pack for long correct? They (ESS/Battery packs) do grow over time in CAC as time passes, reach a ceiling, then being to drop. So in that respect its normal. My replacement legacy pack took over 3 months of constant use/charging/balancing to reach its ceiling and I was lucky enough to have it reach 160 CAC which is the max in theory for that generation
    .
     
  6. Curt

    Curt Roadster Signature #55

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    The Battery Upgrade was done on 1 March 2017, so no, I haven't had it long.

    However, CAC has been falling the entire time (from 215.0 to 208.75), and this bump puts it back to where it started in March.
     
    • Informative x 1
  7. Curt

    Curt Roadster Signature #55

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    So....

    It turns out that after the Service Center had my Roadster for six weeks, and replaced the Pedal Box, PEM, and VMS, the problem remains.

    It's another hot day here in the Washington, DC area, and on my way to a car event, the Alert 972 came back. Only happened twice, but I felt it was prudent to turn around and go home.

    Not happy about this at all.
     
  8. slcasner

    slcasner Member

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    What's left, wires and connectors?
     
  9. Curt

    Curt Roadster Signature #55

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    That's about it. But they claim to have gone over and tested the wiring and connectors from end to end BEFORE replacing the PEM.

    I get the feeling they are just blindly replacing parts, and the PEM is their favorite part to replace whether it is needed or not.
     
  10. PV-EV

    PV-EV Member

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    Last winter I experienced a bunch of (seemingly unrelated) errors. The car had been sitting undriven and was fine when parked. After reviewing the logs, Tesla wanted me to send the car to them in Seattle and, you guessed it, probably swap PEMs. They finally decided that maybe a Ranger could have a look first (ship to Seattle $4k round trip) but that might be several months. I pulled the PEM, cleaned it thoroughly, cleaned all the connectors and applied anti oxidant electric grease to all the pins. I replaced the contacts in the connectors for the blowers and also replaced the pins in the APS connector. Upon reassembly, the car powered up with zero errors and has driven perfectly all summer. Moral of the story: the connectors to the PEM live in a challenging environment and some might be under engineered. A lot of different signals and power go through those connectors. It is relatively easy and certainly inexpensive to do this maintenance. I always wonder how many PEMs get swapped needlessly. Not to say that there is nothing wrong with your PEM, but...
     
    • Informative x 2
    • Helpful x 1
  11. Gremlin

    Gremlin Member

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    Curt its Foster. Learning a lot just reading your post. Had no idea
    Curt, thanks for the posting as I learned a lot (Foster). Still interested in getting a Roadster but have to pay off this car first : P. Nice seeing you and thanks for the offer to help me obtain one.
     
  12. Curt

    Curt Roadster Signature #55

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    Following up on this thread...

    After the first three times I was told that this was fixed, I still encountered Alert 972 in October of last year.

    It took until February of this year for my Service Center to get parts for a "PEM Correction", then they told me that they were "very confident" it was finally fixed. Of course, there was no way to know until hot weather returned.

    Today was my first serious drive on a hot day since then. Temperatures ranging from 98-104F, and I was pretty nervous the whole time, trying to stay close to the shoulder so I could coast off of the highway if needed.

    The car didn't try to kill me today!

    I did get several 1073 (DMC FW: PhaseA OverTemp warning. Torque limited) and 1077 (DMC FW: PhaseC OverTemp warning. Torque limited) messages, but I can accept that on a long, hot drive.

    Anyway, one data point is not sufficient to declare victory, but it's a start. Perhaps future hot weather dives will be a bit less nerve-wracking.

    Stay tuned...
     
  13. hcsharp

    hcsharp Active Member

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    I got this error today. 972 Accelerator Error Fault. Car coasted to a stop on the side of the Interstate. Would not clear despite doing a cold reset a couple times. I had to be towed home. If anybody has any insight please chime in.
     
  14. PV-EV

    PV-EV Member

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    The accel pedal signals route through connectors on the PEM. I know they are small current signals but those pins tend to oxidize and fret from vibration over time. Actual accel pedal problems seem pretty rare.
     
    • Like x 2
  15. hcsharp

    hcsharp Active Member

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    After getting the car home I tried to pull the logs and it failed with the message "VMS - VDS Comms fault". To me that's more evidence that there's a poor connection to the PEM. Then after a couple hours the car started normally and drove. I've never had a problem with the fan connectors but I clean them regularly. I'll find some time to pull and clean the PEM and connectors. I just tried the car again and it went into gear normally but I'm afraid to drive it.
     
  16. PV-EV

    PV-EV Member

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    I agree. Classic PEM connector symptoms, especially since it has gone back to working.
     
  17. hcsharp

    hcsharp Active Member

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    I pulled the PEM. All the contacts look bright and shiny brand new. I'm not surprised. I clean them with DeoxIT D5 and sometimes coat them with electrical grease to prevent corrosion. Since I haven't found a smoking gun I have no idea whether I've fixed the problem. I'm afraid to drive anywhere.
    [​IMG]

    BTW here's a pic of my PEM intake. I haven't cleaned it in 14 months. Despite driving daily on dusty dirt roads there's no debris whatsoever and very little dust. It looks like my hi-flow filter system is working pretty good. My PEM never gets hot. I'll save the details for another thread.
    [​IMG]
     
    • Informative x 1
  18. X.l.r.8

    X.l.r.8 Supporting Member

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    What about the connector at the dash end.

     
  19. hcsharp

    hcsharp Active Member

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    I was hoping to avoid having to lay upside down with my head in the foot well. I remember seeing a board down there with some relays and other stuff mounted on it. Or is it the board the gear shift buttons go to?
     
  20. dhrivnak

    dhrivnak Active Member

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    I would think it is the connector at the top of the accelerator pedal.
     

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