simple fix on steering angle sensor (sas)
The "ESP inoperative See Operator's Man" just came on. Other than the warning on the dashboard, I haven't experienced or noticed any changes in the driving performance.
I checked for codes and there weren't any. I have a Bluedriver OBD2 if that makes a difference. If the steering angle sensor (SAS) is the problem, should I see a code for it? Or shouldn't the fact that the ESP light is on trigger an error code?
I tried several times to reset the SAS with the lock to lock procedure but that didn't fix it.
Some have posted that the SAS needs to be replaced, while others have just cleaned it. How will I know if I can just clean it instead of buying a replacement?
Somebody mentioned to check the brake lights and they appear to be working fine.
Any advice would be greatly appreciated!
The "ESP inoperative See Operator's Man" just came on. Other than the warning on the dashboard, I haven't experienced or noticed any changes in the driving performance.
I checked for codes and there weren't any. I have a Bluedriver OBD2 if that makes a difference. If the steering angle sensor (SAS) is the problem, should I see a code for it? Or shouldn't the fact that the ESP light is on trigger an error code?
I tried several times to reset the SAS with the lock to lock procedure but that didn't fix it.
Some have posted that the SAS needs to be replaced, while others have just cleaned it. How will I know if I can just clean it instead of buying a replacement?
Somebody mentioned to check the brake lights and they appear to be working fine.
Any advice would be greatly appreciated!
I had cleaned the SAS thinking that may be the cause of my ESP error. It wasn't that dirty at all.
When you decide to change your brake light switch, don't be stupid like I was and order the wrong part from eBay. Remove the 3 screws under the dash and look at which switch you have prior to ordering, in fact, take it out and make sure it moves freely. There is a 2 pin model and a 4 pin model. I received the 2 pin model from eBay and when I went to replace my original I realized I in fact had a 4 pin model. So I played with my old brake light switch before putting it back in it's place, moved the switch in and out.
Ever since I did that I have not received the ESP error. In the meantime I had ordered the correct part, which turned out to be cheaper than the wrong one, and I have not yet installed the new part since the old one seems to be working again and not causing ESP errors.
As far as you OBDII scanner goes, you may need a more MB specific scanner that can read the more specific system codes of your MB. Other forums mention the iCarsoft MBII which I picked up thinking I would need it after getting the frequent ESP error but I have not yet actually used.
Message goes off when engine is off and back on. Message comes on as soon as the car is moving/driving and stay on until turning off the engine.
Thanks to Erythros, replace Brake light switch ($32 from FJ MB dealer) problem solve.
all live values read off iCarSoft seem valid for steering angle and close on ABS sensors speeds, I live in the sticks so most testing done on barely paved roads at best but ABS speeds or relative wheel velocities are similar to my Kia, Genesis, Jeep etc. it's only $80 to get all new ABS sensors and working in motorcycle industry I replace them constantly anyway, I know they don't last forever and bikes use literally THE SAME BOSCH sensors. So those are in my shopping cart. It's been 47,000 miles since I've had my cruise control due to this issue. The brake wear item is known to me, quite literally the fronts are pushing 6mm thinner/worn disks per side then new even with newish pads and the rears about 3mm total wear, SBC knows this (and SBC system was replaced IN FULL by mercedes at 190k miles after its 4th failure. Disks and pads are in my shopping cart. Should I just add a brake switch even though mine bench tests fine and plan on trying to clean and re-teach SAS Again?
basically ignore the mileage, I'm keeping the thing till it dies, next major job is a steering rack ($470 rebuilt with $260 core from TRW) so I'm sure I'll get to repeat SAS learn project soon enough. What would you do if it were your car provided you planned on keeping it for your daily hundred mile commuter car? Runs like a top and rather rat rodded for a Benz diesel, strange affinity for this car though I've others arguably much better overall.

That's a viable potion. Gotta do steering rack and inner tie rods soon so....money really, being cheap. Car has effectively zero cash value, just a daily at 213k miles so if cleaning works, great, if not part is cheap enough, already in shopping cart with 4 new ABS sensors, disks and pads all around, the cool looking ones with slots and cast holes lol. RatRod gotta ratrod. All these euro toys add up, thankfully most hold value or appreciate except daily drivers
The Best of Mercedes & AMG
The front disc of steering sensor. Removed and cleaned both sides with rubbing alcohol. Held up to light to make sure no haze was there after.
Whole thing taken apart (while still mounted to the steering column, no need to take it off for servicing the angle sensor)
The main component. On mine the white peg had ran off the sensor's tracks (see last pic) after I had my rack and pinion refurbished and reinstalled. I noticed my old clock spring had a serious amount of grease inside of it, and it was actually oozing out onto the angle sensor. I expect that's how most sensors get messy.
The light disc, top view. Handle this with extreme care because scratching it up will most likely ruin it. I cleaned this with a few Q-tips and some 96% denaturized alcohol. Gently rubbing and drying, making sure the q-tip doesn't leave any fuzz behind.
Underside of the light disc. Here you see the track the white peg has to follow. Easiest way to install this is by placing the peg in the center of it's available space, and gently putting this disc over it, reinstalling the cap and the little ring (make sure you install the ring properly, it only fits 1 way!). Once that is installed gently start rotating it. The white peg will eventually fall into a slot on the light ring and after a few turns you will feel when you reach the end of the track.
Once the peg is back in it's slot you can "reset" the angle sensor following the instructions on the sensor itself, reinstall the whole thing and with some luck your issues will be gone!
These clips are available, but come from China. Such as here. I ordered one but it will take several weeks to arrive.
In the meantime, I decided to try Gorilla super glue to attach the broken off tip.
The instructions on putting back the sensor can be challenging at first. I found a nicely done video that explains exactly how to do this.



