I thought I would post this while still fresh in my mind. After reading so many posts of failed eMMC cards, I decided to act preemptively on my 2016 MX 75D (AP1, MCU1) and remove my eMMC card for Tony to upgrade. The final straw for me was reading
@ohmman ‘s MCU failure saga while on a camper towing vacation.
David and Tony’s videos on post #1 are fantastic, but they are done on an MS 85. There are some differences on the MX as I found out today while removing my eMMC card. So below are my observations. I can only claim that they apply to an Aug 2016 MX build and have no idea if anything has changed in later models. My comments are organized by the time stamps on David’s YouTube video, “How to Remove the MCU from a Tesla Model S/X”
Initial Recommendation: Because further below you’ll see I recommend disconnecting the 12 V battery, take these steps first, in addition to all the prep items Tony lists on Post #1:
- lower the front windows. After 12 V is disconnected the windows will not auto-lower to clear the trim. Plus, with no 12 V, the exterior door handles will not work and you will need to reach inside for the mechanical latch.
- Open the frunk, and stuff a rag in the latch so that it won’t accidentally be re-locked.
2:40 There are no key FOB antennae on either end cap cover.
3:16 This screw under the steering wheel does not exist in the MX. There is a protruding pin in the frame which catches a notch in the cover. The pin does not have to be removed. Just push forward slightly on the plastic cover at the base to release the notch from the pin.
9:56 There is no bottom screw on the MX.
10:39 There is only one fuse box under the hood, but the MCU fuse is not in there. The MX does not have the red fuse box shown in the video. There is a second fuse box in the cabin to the right of the accelerator pedal, behind the carpeted vertical panel of the center console (see my photo). This cover is a son-of-a-gun to get off. It is held in place by clips only but it’s hard to get the correct angle to pull it off. I recommend starting at the rear of the panel and working forward to the accelerator. The black and white fuse box diagram Tony provides on post 1 of this Wiki matches the MX fuse box and shows the location of fuse F235. Inside the box is mounted a fuse puller for removing the micro-fuses so you don’t need any tools for this.
Some additional recommendations: 1) power down the vehicle using the center display and while standing outside the car (no pressure on the seat). Then pull out the fuse making sure you don’t depress the brake pedal, 2) after pulling the MCU fuse F235, the center display did not turn on when re-entering the car, as expected, but there were still LEDs illuminated in the back of the MCU rack indicating certain components were still powered up. So before removing the numerous connectors behind the MCU, I removed the frunk liner, tub, and air filter to expose the 12 V battery, and disconnected the negative lead.
10:49 The MX has a grounding wire at the top of the MCU. Remove this before unscrewing the T-25 torx screws holding the MCU. The ground wire connection is a simple slide on connector with no tab.
14:21 The MX does not have the external Bluetooth antenna.
16:09 The MX only used Torx 8 (no Torx 6) for the screws holding the eMMC card.
@EV-Fixme (Tony) If you think the above might be valuable, I recommend you include them as an addendum to Post #1 of this Wiki.
Finally, let me say that Tony and David’s instructions and videos are outstanding and were a huge help.
Edit: forgot to add the photo.
