Steering assist reduced ... Not a steering rack but bad ground.

[z0lt3c]

About 2 weeks ago, while reversing in my driveway, during a hard turn left, I lost power steering and received the service alerts "steering assist reduced" and "park assist unavailable." Took the vehicle to Tesla who diagnosed a $4200 steering rack. Declined the repair and paid only the required $200 diagnostic fee. Did some research online, and discovered the power steering motor ground was corroded, and upon my attempt at removal, it detached from the frame. I taped out a new, relocated, hole and resecured the ground with bolt and washers, I now have power steering again.

I am a little upset that not only did Tesla mis-diagnose the problem, I paid them $200 for the bad diagnosis.

 

[android04]

About 2 weeks ago, while reversing in my driveway, during a hard turn left, I lost power steering and received the service alerts "steering assist reduced" and "park assist unavailable." Took the vehicle to Tesla who diagnosed a $4200 steering rack. Declined the repair and paid only the required $200 diagnostic fee. Did some research online, and discovered the power steering motor ground was corroded, and upon my attempt at removal, it detached from the frame. I taped out a new, relocated, hole and resecured the ground with bolt and washers, I now have power steering again.

I am a little upset that not only did Tesla mis-diagnose the problem, I paid them $200 for the bad diagnosis.

Good job with the DIY fix. If you want to avoid the ground connection corroding again in the future you can apply some silicone grease on it.

 

[z0lt3c]

Thanks! Not pictured, but I did cover it in white lithium grease. I've got the same can, from like 1982, that I am still trying to use up. That said the new location will make it much easier to inspect and/or address, if needed, in the future.

 

[TLLMRRJ]

Good job with the DIY fix. If you want to avoid the ground connection corroding again in the future you can apply some silicone grease on it.

This stuff would be much better for converting any rust and also a much better way to protect from new or additional rust. Since we are not concerned with conductivity of the product in this application, like we would be with a wire connector, there's no need to use a dielectric silicone grease, that will wash away anyway.

Amazon.com

 

[Du30]

About 2 weeks ago, while reversing in my driveway, during a hard turn left, I lost power steering and received the service alerts "steering assist reduced" and "park assist unavailable." Took the vehicle to Tesla who diagnosed a $4200 steering rack. Declined the repair and paid only the required $200 diagnostic fee. Did some research online, and discovered the power steering motor ground was corroded, and upon my attempt at removal, it detached from the frame. I taped out a new, relocated, hole and resecured the ground with bolt and washers, I now have power steering again.

I am a little upset that not only did Tesla mis-diagnose the problem, I paid them $200 for the bad diagnosis.

WOW! $4200?! what model and year? not covered under warranty?

 

[McBeath]

Just had the same warning come up on 2023 Tesla S. Warning came on as I was preparing to leave supermarket for 4 minute drive home. Steering felt very firm but was driveable. Called Tesla service when I got home who said to bring it in and they would supply a loaner while it was being checked and repaired. Could take up to 2 weeks if they needed parts. I asked if the 2 button reset would clear it. He said very unlikely but try it. I returned to the vehicle, put my foot on the brake and no warning came up! Did this twice putting into Drive and still no warning. Did double button reset anyway and warning still not there! Hopefully was just a glitch but will now monitor closely. Apparently this was an issue sorted out by October software upgrade, but maybe not completely cured it.

 

[z0lt3c]

WOW! $4200?! what model and year? not covered under warranty?

It's a 2017 Model S 100D. Yes, it was out of warranty. Fixed for under $10.

Just had the same warning come up on 2023 Tesla S.

The steering rack setup is a bit different on post-refresh MS.
I would certainly like to think a 2023 would not have developed any corrosion problems yet!
However, if the problem comes back after a rainstorm, or driving through a puddle, I would get it looked at.

 

[MFrunkerOG]

I have gotten the same error a few times on my Oct 2021 plaid. It goes away the next time I drive it. There is no actual reduction of steering assist, just the warning pops up.

Anyone have a pic of where the steering assist ground is? I can’t find it on the service site

 

[ktrbrg]

This week I had a similar issue. Initially, a couple of jolts mid-corner, through which I ended on the other side of the road.
Fortunately, there was no oncoming traffic. A few kilometers later steering assist was permanently gone.
At home, the service mode showed GTW_w036_epasMia.
I had been checking the internet for possible causes and tried several e.g. two button reset, 12v battery, etc.
With the front of the car open the next step was to check the wiring and connectors.
The ground cable came loose with minimal force and I was almost certain to have found the cause.
As a temporary measure, I added the ground cable to the bracket mount next to the original connection, which solved the issue.
My perception may be skewed after a brief period without steering assist, but I believe it may be slightly stronger (better electrical connection).

 

[MFrunkerOG]

This week I had a similar issue. Initially, a couple of jolts mid-corner, through which I ended on the other side of the road.
Fortunately, there was no oncoming traffic. A few kilometers later steering assist was permanently gone.
At home, the service mode showed GTW_w036_epasMia.
I had been checking the internet for possible causes and tried several e.g. two button reset, 12v battery, etc.
With the front of the car open the next step was to check the wiring and connectors.
The ground cable came loose with minimal force and I was almost certain to have found the cause.
As a temporary measure, I added the ground cable to the bracket mount next to the original connection, which solved the issue.
My perception may be skewed after a brief period without steering assist, but I believe it may be slightly stronger (better electrical connection).
View attachment 962154View attachment 962155

Do you have a slightly wider pic of where exactly this ground bolt is

 

[Goransol]

I have gotten the same error a few times on my Oct 2021 plaid. It goes away the next time I drive it. There is no actual reduction of steering assist, just the warning pops up.

Anyone have a pic of where the steering assist ground is? I can’t find it on the service site

Same error, and I tried to check but I cannot find where this bolt is. Does anyone have a guide or a wider picture to show where the bolt is situated in a 2017 75D or similar models.

Would help out alot, I am certain that this is my issue as well, and spending thousands on repairs is not really something I want to do.

 

[z0lt3c]

Here is a wide view of the location on my 17 S100D. Note the white circle.

The connection is kinda tucked behind a metal bracket, which makes it hard to see.

(this is what a NJ car from 2017 looks like!!!)

 

[Goransol]

Thanks, that helps out a lot.
I need to disconnect the battery and power before doing anything here, right?

 

[Goransol]

Just want to pop in and say that I fixed this yesterday. Ended up drilling a new hole next to the broken bolt, and everything is back to normal.
Saved me alot of money, all it took was a couple of hours of work.

Thanks again!

 

[Unpilot]

Here is a wide view of the location on my 17 S100D. Note the white circle.

View attachment 965301

The connection is kinda tucked behind a metal bracket, which makes it hard to see.

View attachment 965302


(this is what a NJ car from 2017 looks like!!!)

What month was your car built? I just had the same message and have no power steering. My car has been sitting unmoved for about 45 days.

When I looked for that ground wire, I see I have a different look than yours. (mine is a 2017 Model S 100d as well) Built in late 2017 so I assume they made a change. Here is a picture of what I assume in the ground wire now.

At any rate, I have tried cleaning those connections and still have no power steering with the EAP-w001 error message.

 

[David Harvey]

About 2 weeks ago, while reversing in my driveway, during a hard turn left, I lost power steering and received the service alerts "steering assist reduced" and "park assist unavailable." Took the vehicle to Tesla who diagnosed a $4200 steering rack. Declined the repair and paid only the required $200 diagnostic fee. Did some research online, and discovered the power steering motor ground was corroded, and upon my attempt at removal, it detached from the frame. I taped out a new, relocated, hole and resecured the ground with bolt and washers, I now have power steering again.

I am a little upset that not only did Tesla mis-diagnose the problem, I paid them $200 for the bad diagnosis.

I’m afraid that your pictures are not displaying. Do you have another way of sharing them please?

 

[z0lt3c]

This post shows where my ground connection was found;
Steering assist reduced ... Not a steering rack but bad ground.

This was the picture of my original ground connection condition.

And here was the finished repair showing the new ground connection.