How to troubleshoot electronic steering ML250
Thread Starter
Member
Joined: Apr 2007
Posts: 97
Likes: 1
From: Doylestown (Bucks County) PA
2015 ML250, 06 E320 CDI, 2008 GL320 (sold)
How to troubleshoot electronic steering ML250
My ML250 (4 cylinder diesel) has electronic steering and its getting harder to turn. thought I need to change the fluid but doesn't have any....electronic steering.
Any idea on how to troubleshoot this type of steering system? thanks....Ed
Any idea on how to troubleshoot this type of steering system? thanks....Ed
Out Of Control!!
Joined: Apr 2019
Posts: 11,924
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
simple + in-depth
Surprisingly the electric rack is a faily good unit. Steering disfunctions based on external reasons. Not do much the rack until it gets water soaked.
The front struts top ball bearings use sticky grease that evaporate to make steering harder to turn L to R and seek its Center.
The steering rack takes inputs from the Steering Column optical sensors across CAN and Gateway. The SCM benefits from good soldered connections and a freshly rebooted car.
Then the steering becomes really nice to drive... being "biased straight" instead of acting toed-out all over.
As @rapidoxidation points out : scanning faults is the top step. Modern steering depends on timely module data.
The front struts top ball bearings use sticky grease that evaporate to make steering harder to turn L to R and seek its Center.
The steering rack takes inputs from the Steering Column optical sensors across CAN and Gateway. The SCM benefits from good soldered connections and a freshly rebooted car.
Then the steering becomes really nice to drive... being "biased straight" instead of acting toed-out all over.
As @rapidoxidation points out : scanning faults is the top step. Modern steering depends on timely module data.
Last edited by CaliBenzDriver; Jan 17, 2026 at 03:37 PM.
Thread Starter
Member
Joined: Apr 2007
Posts: 97
Likes: 1
From: Doylestown (Bucks County) PA
2015 ML250, 06 E320 CDI, 2008 GL320 (sold)
Surprisingly the electric rack is a faily good unit. Steering disfunctions based on external reasons. Not do much the rack until it gets water soaked.
The front struts top ball bearings use sticky grease that evaporate to make steering harder to turn L to R and seek its Center.
The steering rack takes inputs from the Steering Column optical sensors across CAN and Gateway. The SCM benefits from good soldered connections and a freshly rebooted car.
Then the steering becomes really nice to drive... being "biased straight" instead of acting toed-out all over.
As @rapidoxidation points out : scanning faults is the top step. Modern steering depends on timely module data.
The front struts top ball bearings use sticky grease that evaporate to make steering harder to turn L to R and seek its Center.
The steering rack takes inputs from the Steering Column optical sensors across CAN and Gateway. The SCM benefits from good soldered connections and a freshly rebooted car.
Then the steering becomes really nice to drive... being "biased straight" instead of acting toed-out all over.
As @rapidoxidation points out : scanning faults is the top step. Modern steering depends on timely module data.
What codes would you expect to see. Great to hear that the electronic steering is a robust system.
Out Of Control!!
Joined: Apr 2019
Posts: 11,924
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
Steering Assist Matters
Thanks for the detailed response. Im away from my scanner for a few weeks.
The car has 110K on it and my wife loves her car! Anything you can do for the top strut bearing (grease gun with needle fitting perhaps).
What codes would you expect to see.
Great to hear that the electronic steering is a robust system.
The car has 110K on it and my wife loves her car! Anything you can do for the top strut bearing (grease gun with needle fitting perhaps).
What codes would you expect to see.
Great to hear that the electronic steering is a robust system.
Hard faults from the rack are well monitored with self-check during ignition power up.
Many external conditions help degrade a good rack effectiveness:
- Busy CAN-Bus slow traffic (CGW)
- Marginal Steering column (SCM)
- front tire pressure (38Psi)
- wheel alignment + bearings play
- suspensions parts (bushings, ball joints, strut bearing, tie rods)
Strut bearing lube:
The only way I know to lube this bearing is to open it up... clean the old sticky left over and provide new upgraded high-temp silicon grease. This step made my steering 50% lighter.
About one quarter of the vehicle weight is carried by this bearing and more during braking efforts.
While you're there replace a new top bearing unit to benefit from its new center bushing (plus upgraded grease). In addition consider the strut itself: leaking or ok?
Parking efforts
It is to be expected that steering all the way side to side without motion is extraneous. Drivers who grew up without any steering assist learned to steer their wheels with car in motion.
++++ SILVER BULLET?
You're going to get lucky... if you find crazy unstable modules, related or not.
Unstable modules have the power to overwelm the Bosch network gateway (CGW) with junk traffic.
Deal with these modules and reset them back to fault free stable for a while.
Lastly whole chassis Reboot for VIP modules that are always powered in 24x7 SAM + CGW.
Last edited by CaliBenzDriver; Jan 20, 2026 at 04:31 PM.
Thread Starter
Member
Joined: Apr 2007
Posts: 97
Likes: 1
From: Doylestown (Bucks County) PA
2015 ML250, 06 E320 CDI, 2008 GL320 (sold)
You can feel the steering is hard while in motion. It doesn't self center after turning. I will work on the bearing when warm weather returns.
Thanks for the advice.
Thanks for the advice.
Out Of Control!!
Joined: Apr 2019
Posts: 11,924
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
cheap refresh parts
While removing the struts to replace bearings also replace new stabilizer bars attached with rusted old hardware. SB's are responsible for making the chassis bouncy side to side, not the struts.
You will be pleased with the difference in handling.
Last edited by CaliBenzDriver; Jan 21, 2026 at 11:20 AM.
Trending Topics
MBWorld Fanatic!
Joined: Jan 2016
Posts: 2,749
Likes: 880
From: In the Shadow of the Tetons
2013 ML350 Bluetec
When you're driving straight ahead on a flat (not crowned) road, does your steering wheel rest in the straight ahead position or is it cocked to one side? In other words, how's your alignment?
MB World Stories
The Best of Mercedes & AMG
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
