-AJC-

Hi all,

My 2006 320 CDI has airmatic and ADS. I've recently changed airmatic compressor, relay and level sensor control arms for genuine Mercedes parts.

The ADS button gets stuck in Sport mode after a few minutes driving. You can select Sport, Comfort or Auto mode when you first start the car but it will always revert to Sport mode after a short while.

I've scanned for codes and the only one is the Steering Angle sensor, which puts the EPS light on. Was advised by Mercedes mechanic that this will be due to the tracking being out and the fact that the steering wheel is offset to the right to keep the car driving straight . I get no airmatic warnings like visit workshop etc. and the car raises to off road 1 and 2 and back to normal without any issue. Car also holds pressure and does not drop on any corner when left for a few days.

I changed all the ABS plastic control arms from the level sensors as the originals were past their best and had become quite pliable. I've also checked all fuses and all ok.

Has anyone had a similar problem and can shed some light?

Cheers

Andy

Maj. Dundee

Start the truck, center the steering wheel and then turn the steering wheel all the way to one side and then the other and center again and see if the light goes out.

-AJC-

No, tried this and light stays on - assume you mean Warning Triangle light? Been told this is caused by steering angle sensor and won't be cured until I get the tracking done.

sclasspilot

Long time lurker, first post.

Had exactly the same symptoms when I installed a new strut and accidentally bent one of the electrical connection pins.

Check your wiring connection to the struts.

I had no dash error messages and no codes. The only symptom was the car was stuck in sport mode and very hard suspension.

2008 ML320 with airmatic.

sclasspilot

And the delay also backs this up - suspension movement is causing the wire to lose the connection. It will be difficult to check as the wiring between the connector and the strut as it is all sealed. Run some string down there and jiggle it after starting the car (but before moving off).

-AJC-

How did you bend one of the electrical connection pins? The only electrical connectors I can see for the airmatic strut are ABS plastic connectors and will only fit one way round. Do you mean I need to check these to ensure they are seated correctly?

sclasspilot

The strut was supplied with the pin slightly bent. Tried to straighten it but it didn't make the connection and exhibited the symptoms as described. I made up a short length of fine wire to replace the pin as it broke off.
In your case it's likely to be internal damage to the wire between the inner guard and the strut, or a faulty/dirty connector which is opened by the suspension movement.

How do you know it's making a good connection?

-AJC-

I'm still unsure what pin you're referring to?



I have been following this video that explains how to replace the front strut:




The shock control I assume refers to the ADS function and specifically the electrical connection for the ADS cylinder circled in this image






All of the wiring around this cylinder is sealed from the factory.




The only electrical connection required is the plug connection that is circled in this image




Where exactly is the pin that you refer to?

sclasspilot

The pins (there are actually three of them) are the connectors inside the electric terminal that you circled.

This terminal may have a faulty connection, or the wire between connector and the damper has broken internally. Do a visual inspection of all four corners and clean all the terminals. You will have to remove the inner guards on the front, which only takes 5 minutes once the wheel is off.

Failing that, the diagnosis software at your Mercedes mechanic can tell which strut is not returning the required readings.

-AJC-

I've found the cause of the problem.

The Steering Angle Sensor (N49) was faulty and needed replacement.

After fitting the new item recalibration was possible as Maj Dundee had described (turning wheel lock to lock x5 times) and the ESP light went out.

Now the ADS button works as advertised.