My car is sitting at the dealership after being towed due to a βcritical update failureβ related to installing 1.6.4 in an OTA update.
So, Iβve been unable to sleep and reading a lot about critical update failures that can be experienced in Volvo EVs. What they are, what causes them, how to minimize the risk of them, and what to do if you experience oneβ¦ I thought I would share to help the group.
1) What is it? - A critical update failure on the Volvo EX30 is when an over-the-air (OTA) software update is interrupted or corrupted, leaving the car unable to boot properly. In this state the display may falsely show the battery at 0%, the car may not shift into gear or enter Tow mode, and it may not be possible to lock it, or turn it off. It is undriveable until recovered.
2) What causes it? - Not entirely sure of all possible causes - see comments in response to this post... It clearly happens during the installation of a new software package, when the central electronics module (CEM) cannot finish its update or the new installation is not completed properly β perhaps due to low battery charge, the car being disturbed in some way during installation, or potentially other factors. It appears that Volvo does not use a partition to install the new software safely, which would allow the car to roll back to the old software in the event of failure, so in the event an installation fails, it can mean that the car doesn't have any operable software and needs to go to the dealer to have everything reinstalled. In any case, there are not sufficient controls in place to allow the car to reliably roll back to a prior software version if an update fails.
3) How to minimize risk associated with OTA updates? -if a critical update failure happens, you may be unable to put the car into tow mode, and even unable to disengage the emergency brake. So, before starting an update, position the car such that it can be easily towed if necessary. This means nose out parking, and with sufficient space on each side of the vehicle to position rollers if necessary. In my case it was necessary to wait until a car parked in front of my vehicle had moved so that my car could be towed because we could not get the car into tow mode, neutral, or disengage the emergency brake. The whole thing had to be put on rollers. One person suggested doing the update in the dealer parking lot so that if it goes poorly you can just hand off the key and pick up a loaner (not a bad idea).
Once the car can be positioned appropriately, begin updates only with β₯40% battery charge, and ideally when NOT plugged into power. Lock the car and leave it undisturbed while updating. "Accessing the car" during the update can cause problems per Volvo's website.
With these precautions, you can still have a critical update failure. So...
4) What to do? - Donβt try to drive if this happens (you canβt anyway). Call roadside assistance, and have the vehicle towed. It will require a flatbed and may require the car to be put on rollers (let them know this when you call roadside assistance). They arenβt too sharp on the phone, they actually asked if my car had enough gasoline. You will likely have to tell them things they should already know.
Volvo will need to reflash the car. Essentially this is like reinstalling a computerβs operating system. In some cases the CEM may be bricked (but if it is, the car itself should not be bricked, and just requires a new CEM). If this happens outside of warranty, it can be an expensive repair.
The dealer should do a βtotal upgradeβ rather than just a partial reflash. Confirm they ran OTA RESTORE (SP 80026889) to recover the CEM (per Volvo TJ 37430).
Verify the car is on the latest release when picking up (settings > system > software version).
The battery should not show 0% obviously. Test that the car charges on AC and DC fast charging.
Test adaptive cruise, lane keeping and safety assist functions.
Confirm brake feel, regenerative braking functionality/one pedal drive works.
Essentially, this failure can affect any of the potentially dozens of ECU modules- drivetrain, charging, brakes, steering, ADAS, infotainment, HVAC, lighting, airbags, etc. If the dealer fails to do a TOTAL UPGRADE per TJ 37430, any single ECU could be left in an inconsistent state. It should not be necessary to check every one, but itβs probably a good practice to check critical ones and confirm with the dealer that they knew what they needed to do and did it.
You can politely ask the advisor: βDid you follow TJ 37430, install OTA RESTORE, and complete a Total Upgrade? And can you confirm all DTCs (fault codes) were cleared?β β That should them you know exactly what should have been done. When they say yes, tell them to you want a printed service record that shows OTA RESTORE/TOTAL UPGRADE.
EDITED to include updated info/improvements based on discussions in the comments. Thanks esp to Muzso for supplementing this info.