W221 Suspension Malfunction

[S350L]

Good evening all,

Just driving home in my W221 S350L Bluetec, when the suspension became rock hard and the word MALFUNCTION in yellow and the pic of the car with an up arrow appeared on the dash. I pulled over to get out to have a look and almost needed a step ladder to get down from the car, as it is about 18 inches off of the ground. I switched it off and on again, but this didn't help and the words, vehicle rising briefly, appeared on the dash.

Has anyone come across this before?

I seem to remember reading somewhere that the air system can be reset by disconnecting the battery. is this true?


Thanks in asdvance

Si

 

[whitenemesis]

Check the level sensor arms are still attached front and rear. If nothing obvious get the car on STAR and find out what's what..

 

[S350L]

Check the level sensor arms are still attached front and rear. If nothing obvious get the car on STAR and find out what's what..

Thank you so much for the swift reply. How would I check the level sensor arms?

Thanks

Si

 

[whitenemesis]

Visually. They are usually attached between the bodywork and the suspension. On the front to one side of the anti-roll bar and on the rear to the centre of the rear axle.

 

[Petrol Pete]

They look a bit like this , they can fail or the plastic link arms pop or break off.

 

[zipdip]

Yes the level sensor is the first place to look,it is rear passenger side,as a temp repair you could use a once only to hold the arm in a position and then see where that leaves your car's ride height,it is hardly ever the sensor that goes it is the plastic/nylon that cracks,I have know people repair it with a plastic wield compound.

 

[S350L]

Thank you guys, I'll have a look in a bit. I won't need to jack it up, I can almost walk underneath it

 

[Petrol Pete]

Maybe , but don't get under it and mess about without propping it up securely , it might just drop itself !!

 

[S350L]

The car is uniformly high all round, not on one corner. Could this be a sensor or something else?

 

[S350L]

Actually, the rear is higher than the front. The front is a little higher than usual but the rear is really high. Never seen it that high.

 

[pillow]

You have:

Sensors for each of the front wheels
A single sensor in the rear

It is very common in the W221 for the clamp that holds the rear rod to rust and snap, thereby breaking the link between the actual rear height and the sensor.

In such a situation the car knows there's a problem because the sensor does not react when the car makes adjustments to the air bags and usually defaults to pushing all corners up.

The good thing is the fix is fairly cheap

 

[S350L]

Thank you, that makes sense. I'll take a look

 

[S350L]

Sorry to be a pain, where is the rear ride height sensor located. I've looked, but can't see it

Thank you

 

[pillow]

Sorry to be a pain, where is the rear ride height sensor located. I've looked, but can't see it

Thank you

You should see it attached to the anti roll bar, just above the differential.

 

[S350L]

I have found it and it's defo the linkage that has broke. Difficulty is, I can't see how to get to it. I looked from underneath, but can't get my hands to it and I don't think there will be room if I removed the wheel and came in from the side

 

[pillow]

I have found it and it's defo the linkage that has broke. Difficulty is, I can't see how to get to it. I looked from underneath, but can't get my hands to it and I don't think there will be room if I removed the wheel and came in from the side

It's tight but you should be able to get to it from underneath. I think it's a 10mm nut that holds the rod to the sensor.

 

[zipdip]

Yes it hardly ever the sensor which goes wrong is just a potentiometer ,it is nearly always the arm or the plastic part that breaks,and you cannot buy the arm on it's own,but there are some on ebay,one of the common causes of this part breaking on a S series is the sleeping policemen in the roads go over one of those two fast and it can bust the ride height linkage,ask me how I know, in my case the car went down onto the bump stops and it ain't no fun driving 10 miles like that to the garage.

 

[S350L]

Yes it hardly ever the sensor which goes wrong is just a potentiometer ,it is nearly always the arm or the plastic part that breaks,and you cannot buy the arm on it's own,but there are some on ebay,one of the common causes of this part breaking on a S series is the sleeping policemen in the roads go over one of those two fast and it can bust the ride height linkage,ask me how I know, in my case the car went down onto the bump stops and it ain't no fun driving 10 miles like that to the garage.

I b

It's tight but you should be able to get to it from underneath. I think it's a 10mm nut that holds the rod to the sensor.

Thank you

I'll give it a go. Don't need a 4 poster ramp, the car is high enough already.

 

[Ted]

I b

Thank you

I'll give it a go. Don't need a 4 poster ramp, the car is high enough already.

Yes, but don’t forget that fixing it might cause it to drop.
Hopefully without you underneath.

 

[S350L]

I've replaced the linkage, which has kind of sorted the problem. The suspension works fine, however, the rear is higher than normal. Do I have to do some sort of reset or do I need to take it to a dealer to re-calibrate the rear suspension

Thx in advance