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Does anyone know if you can reset the Steering Angle Sensor on the W164?
My car has been fitted with a replacement rack and currently with the steering wheel straight the sensor reads about 1 whole turn out. I'm hoping you can reset this to 0 degrees with STAR without having to disconnect the rack and remove the clock spring before making an adjustment.
You still refuse to answer/ignore the question about the revolutions of the steering wheel, and to be very honest with you, you will still have the same problem with the sensor.
The Clock Spring was broken when the rack was replaced because it has a contact tape inside it which will snap if everything is not aligned properly.
But the Steering Angle Sensor has no such tape, therefore it is not broken.
Your entire problem is the result of mis-alignment between the steering column shaft and the rack & pinion. Either or both are not aligned.
You still refuse to answer/ignore the question about the revolutions of the steering wheel, and to be very honest with you, you will still have the same problem with the sensor.
The Clock Spring was broken when the rack was replaced because it has a contact tape inside it which will snap if everything is not aligned properly.
But the Steering Angle Sensor has no such tape, therefore it is not broken.
Your entire problem is the result of mis-alignment between the steering column shaft and the rack & pinion. Either or both are not aligned.
Good luck with the replacement.
To answer your question the steering wheel can be turned approx. 4.5 turns from stop to stop. After just over two rotations the steering wheel is dead centre and the wheels are both straight.
My original question was can the steering angle sensor be calibrated to 0 degrees with STAR or similar.
Having spoken to other ML owners here in the UK and the main dealers it would seem the two parts that provide the steering angle position are the Control Unit (N49) part number A164545871680 and the Contact Spiral.
Both of these items have been broken by the previous owner of my car. I replaced the Contact Spiral (Clock Spring) primarily to restore functionality to the steering wheel controls and horn. However, the steering angle fault remained and was diagnosed on STAR as being due to a faulty Control Unit, exactly as per the link supplied in my earlier post. Both of these parts can be broken if you rotate past their end stops, which is why both are supplied locked securely in the centre position and provide instructions on how to position them correctly if out of sync.
Thought I'd wrap this up having fixed the problem myself this past week and been given some inaccurate info from various garages.
I took the car to an indy specialist to get the SAS calibrated as my local garage did not have access to STAR. The indy charged me £280 saying they had to refit my steering column correctly as it was 180 degrees out of alignment?? This involved removing the entire column from the car by disconnecting it from the rack etc. etc. Utter rubbish!! I drove the car off the forecourt but the ESP light came on immediately. Took it back to them, reconnected to STAR and now they said the SAS was broken and needed to be replaced. Quoted me another 1-2 hours labour plus the price of the part. Not satisfied with their work so far thought I'd investigate myself.
If you look at any diagram of the steering column you can see it would be impossible to fit incorrectly or upside down etc.
However, should you disconnect it from the rack you should do so in the straight ahead position (steering wheel and front wheels) and ensure you refit in exactly the same position. This is simply to prevent damage to the Contact Spiral (clock spring) and Steering Angle Sensor (SAS) switch fitted just behind the steering wheel.
Both of these parts have a dead centre position and allow approx. 2.5 complete turns of the steering wheel either side. If you were to inadvertently reconnect the column with the front wheels straight but with one full turn of pressure already applied to the springs inside both Contact Spiral and SAS then you would most likely break both these springs as soon as you applied full lock during the recalibration process. To be safe its probably a good idea to remove both Contact Spiral and SAS from the steering column before fitting a new rack incase you damage during refitting.
Here are the parts in question.
Contact Spiral (Clock Spring)
Steering Angle Sensor (N49)
Supplied new these come with a red guard on the Contact Spiral and a piece of white plastic on the SAS, locking each part in the dead centre position. If supplied used you will need to make sure they are in the dead centre position before fitting.
These are very easy to fit yourself with various videos on youtube explaining the procedure.
In my case a broken Contact Spiral meant none of my steering wheel controls worked including the horn. The broken SAS produced further faults and error messages including: ESP inactive, ABS warning, Speedtronic inoperative, Active Light Cornering inactive, ADS Sport/Comfort/Auto switch failed to Sport mode.
A brand new Contact Spiral from Mercedes was £85 + VAT with 2 year warranty. A reconditioned SAS also from Mercedes was £145 inc. VAT with 12 month warranty.
Hope this helps if you have similar warning messages.
And what about the revolutions of the steering wheel?
Hi Maj it seems that you are one of the only guys that seems to know what goes with this sensor , maybe you can give me some advice.
I had My steering rack changed, as soon as i left the garage i noticed that the ESP light came on.
Is there a way to reset the sensor to make sure its not faulty ? before trying to change it
With the eng. running, center the steering wheel with the tires, then turn the steering wheel all the way to one side, then to the other side and again center the steering wheel. The light should go off.
If the light does not go off, the mechanic broke the sensor replacing the rack.
I had the same problem , changed rack , as soon as i was out of the garage i notices the ESP light, mechanic told me the my SAS stopped working the minute i left the garage ( it was a good joke) . never returned to the above garage , but had to replace SAS and spring
pulled mine apart today as the eps was popping up, my scanner keep showing the SAS going into fault, just sitting in the drive way worknig the steering wheel side to side gently, so bit the bullet and pulled it all apart, not overly difficult, the hardest part was the cap screw holding the steering wheel on, impact gun and driver sorted that. pull coloum out and dismantled, then pull sensor apart, surface was smeary, so cleaned with glass cleaner and soft cloth, and reassembled, you MUST center the sensor as per instructions on the sensor, there is a spiral track that moves the pick up in and out, get this wrong and it will go out of travel, re assembled the whole thing only to get a airbag fault, i figured out the airbag plug was not in properly, how ever my scanner wont reset it,so to prove this i unplugged the airbag and retested, told me on one line circuilt low, and next same circuit high, so off to a mate with a decent scanner to sort, the esp is fine now, SRS to sort now
07-22-2017, 11:16 AM
