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Power Steering Issue

Need to start with all the car info before the probs:

2014 P85D 108k miles. Had the MCU2 upgrade last week along with replacing the SCCM that i broke while doing the heated wheel retrofit, got the car home on Monday 8 Feb. Error coming up every time i get in the car about AP not working but it worked fine, (GTW_w242). The SCCM they installed was different than the one i had as the AP lever didn't have the cancel button on the end of it. MC2 SCCM, ACC, HEATED VARIANT (1057356-00-B).

I was driving home yesterday around the 300 mile point i was passing another car across a split yellow line and as I was turning right to get back into my lane the power steering went out and an error came up on the screen. EPAS_w001, EPAS_w002, GTW_w181

The road has the "keep awake" bumps and it also has the dimples for the reflectors if any of that matters. I've driven the same road dozens of times and taken the exact same route and passed along the road without issue for almost 3 years now.

So for the last 100ish miles of my trip i was driving with no PS and damn that thing is a b**ch to turn and of course it was all twists and turns for the trip home. Great forearm workout :p

Anyway when i got home i did the brake pedal reboot with no results. then i pulled the firemans loop and the 12v for about 15 min, then put it back together and the PS works as it always has and it turns great, took it for a test drive and no probs and driving to work today its good. HOWEVER, i my AP doesn't work, yesterday it wouldn't work i assume because the power steering was out but now i dono why it wont work. i have the cruise control and that works fine but when i pull the stalk for AP it says Autosteer temporarily unavailable DAS_w207.

I've scheduled an appt at the SC for 2 weeks from now but I'd like to get some ideas of what could be wrong or how to fix it, because I'm a good mechanic and i hate to piss away my money for tesla to do the damn work that i could've done.
 
I have a Mercedes Metris cargo van with the same electric steering unit as my 2015 S85D - both units got the recall for Bosch using steel bolts in an aluminum frame.

The Metris' power steering will stop working after crossing aggressive center divider dots (US-95 in Nevada between Hawthorne and Tonopah) or crossing cattle grates sometimes. I paid thousands to have it replaced only to have the same thing reoccur multiple times. The only solution is to pull over, stop and lock the van. Wait 10 minutes, and it's all fine.

Bosch's software for the electric power steering unit incorrectly faults when the wheels encounter just the right sort of rough surface.

I strongly recommend filing a complaint with NHTSA : File a Vehicle Safety Complaint | Safercar.gov | NHTSA

Don't bother taking it in for service - Tesla can't fix it & they'll just charge you money (like Mercedes did) to try. But, it won't work - the firmware in the Bosch power steering controller is what's wrong. There is no update available. That's why you have to file a complaint with NHSTA
 
The Metris' power steering will stop working after crossing aggressive center divider dots (US-95 in Nevada between Hawthorne and Tonopah) or crossing cattle grates sometimes. I paid thousands to have it replaced only to have the same thing reoccur multiple times. The only solution is to pull over, stop and lock the van. Wait 10 minutes, and it's all fine.

Bosch's software for the electric power steering unit incorrectly faults when the wheels encounter just the right sort of rough surface.

I strongly recommend filing a complaint with NHTSA : File a Vehicle Safety Complaint | Safercar.gov | NHTSA

Don't bother taking it in for service - Tesla can't fix it & they'll just charge you money (like Mercedes did) to try. But, it won't work - the firmware in the Bosch power steering controller is what's wrong. There is no update available. That's why you have to file a complaint with NHSTA

Very interesting, that explains why it fixed itself when i did the firemans loop reboot. And I had the bolt recall fixed a few years ago.

Still cant figure out why the autopilot isn't working though. I think it has something to do with the errors i was getting, i mean they pop up while I'm not in the car and keep occurring like every minute. If you look at the pic the errors are for 10:38 but I didn't even go to my car till about 10:50.
And it started the day i picked up my car from service...

P_20210216_105326.jpg
 
You are not alone, better read this discussion....

That is interesting, I still can't figure out why the AP isn't working. It was working after the upgrade and then stopped working when the power steering went out. But the PS is now working just fine but no AP. All fuses are good, I checked all of them with an ohm meter so I dono why the AP isn't working.
 

David.85D

Active Member
Oct 29, 2016
1,662
1,433
USA
Any chance your 12V battery is on the way out? I had lots of seemingly random errors up until it finally triggered the alert for the 12V battery.

p.s. they had to come out to my house a week after my mcu2 upgrade to do the 12V power reset and reflash the firmware. Something just didn’t take…
 
Any chance your 12V battery is on the way out? I had lots of seemingly random errors up until it finally triggered the alert for the 12V battery.

p.s. they had to come out to my house a week after my mcu2 upgrade to do the 12V power reset and reflash the firmware. Something just didn’t take…

My 12v is about a year or so old. Last time it went out it just popped up with the 12v needs replace error no weirdness beforehand.

I know you can test a normal 12v at autozone for free, but this being a deep cycle battery would it get the same test or is there some other way to check the health of the 12v battery?
 

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