An issue which has stumped Tesla service for the past several years

[oaftobark]

I have an unusual situation with my 2018 Model S -- spontaneously while driving my power steering stops working and my dash starts cycling through several error messages, some of which included (video link):

• Steering Assist Reduced (followed by power steering being disabled mid-drive)
• Park Assist Unavailable
• Lane Departure Avoidance features unavailable
• Regenerative braking temporarily reduced
• Automatic Emergency Braking reduced
• Stability control disabled
• Traction control disabled

Autopilot disables as well and sometimes at red "P" displays on the upper right saying something like "Parking Brake Disabled".

This began ~2-3 years ago, and I have had multiple previous visits at Tesla. The power steering drops out while mid-drive about 7 out of 8 times when I take it out, which has put me in some dangerous spots. Even more confusing, I recently had a mobile visit where the mobile technician also noticed these problems and thought it might be the 12V battery, but he then sent me the following text afterwards:

Something very strange is going on. The alerts that I saw when I was at your house can't be found. It's strange because it's historical data that doesn't get deleted. I'm super confused. If you could reach out to me next time the car acts up, I can try and catch the alerts. I think this is why the diagnostic team couldn't find anything. It's literally not showing up anymore at the time stamp I was at your house.

I asked earlier here and some of you suggested it might be an electrical short caused by a grounding issue (Grounding stud overtorqued), wiring harness or 12V issue. I took it in to the dealer with this information and they're telling me I need to have the steering rack replaced for another $5k. I had a bad hit and run in 2018 where I was struck severely on the front left while I was driving, wonder if this is a residual issue though I don't think I could prove this to insurance ($35k worth of damage at the time).

Right now I am very worried that I will pay for the steering rack to be replaced and stuck with the same issues all over again.

Have any of you had similar issues? Every time I look at this car I feel like I'm throwing good money after bad. Any advice would be sincerely appreciated.

 

[ShawnA]

Hi @oaftobark ,

Do you have MCU1 - car manufactured before March 6, 2018???
If so has the memory upgrade been performed???
Or better yet have you upgraded to MCU2...

I see in your duplicate thread the issue was a defective wire harness...

Good luck,

Shawn

 

[moshermm]

I have an unusual situation with my 2018 Model S -- spontaneously while driving my power steering stops working and my dash starts cycling through several error messages, some of which included (video link):

• Steering Assist Reduced (followed by power steering being disabled mid-drive)
• Park Assist Unavailable
• Lane Departure Avoidance features unavailable
• Regenerative braking temporarily reduced
• Automatic Emergency Braking reduced
• Stability control disabled
• Traction control disabled

Autopilot disables as well and sometimes at red "P" displays on the upper right saying something like "Parking Brake Disabled".

This began ~2-3 years ago, and I have had multiple previous visits at Tesla. The power steering drops out while mid-drive about 7 out of 8 times when I take it out, which has put me in some dangerous spots. Even more confusing, I recently had a mobile visit where the mobile technician also noticed these problems and thought it might be the 12V battery, but he then sent me the following text afterwards:

I asked earlier here and some of you suggested it might be an electrical short caused by a grounding issue (Grounding stud overtorqued), wiring harness or 12V issue. I took it in to the dealer with this information and they're telling me I need to have the steering rack replaced for another $5k. I had a bad hit and run in 2018 where I was struck severely on the front left while I was driving, wonder if this is a residual issue though I don't think I could prove this to insurance ($35k worth of damage at the time).

Right now I am very worried that I will pay for the steering rack to be replaced and stuck with the same issues all over again.

Have any of you had similar issues? Every time I look at this car I feel like I'm throwing good money after bad. Any advice would be sincerely appreciated.

I was having some similar issues with power steering. The grounding lug popped off in the mobile techs hands with a small bit of pressure. There are at least three different types of corrosion on that lug in the winter.

Then we spied that the passenger side main wire harness had chaffing on it.
When I poked at it, after shutting off the car by pulling the first responders loop and disconnecting the 12v battery, I found the back side of the cable to be chaffing too.

There is a small rock hanging out just below the spot of chaffing…

One of the wires is for the front parking assist sensors.


The other interesting idea is that in 2016 there was a Bosh steering rack motor mounting recall.
I can’t tell what type of wax they are supposed to reseal the motor with and if wax means something that looks like melted candle wax or not.