Airmatic suspension problem on w205 C class C350e estate (2016)

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themadsinger

New Member
Joined
Oct 27, 2020
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5
Location
Kettering
Car
2016 Mercedes C350e
Wonder if anyone can provide some suggestions for the cause of my suspension problem

I have a C350e which is 4 1/2 years old. DOne just over 60K miles

2 weeks ago when driving the children home from school the back end suddenly became very bouncy. No warning message on the dash board. I pulled over and checked and the suspension was right down on both back wheels. Looked fine on the front. I got back in the car and switch the ignition back on and it came up vehicle rising on dash display. Suspension came back up to normal level and drove home fine. I went out it in later in the evening and was all fine.

Next morning, on the way to school, got a dash message stayin STOP VEHICLE - VEHICLE TOO LOW. Before I had a chance to pull over that disappeared and when I did pull over (maybe a minute later) The rear and front suspension looked fine. Even when the message was on the car drove fine leading me to think that it was a false warning but I dont know for sure.

On the way home from school that evening, it did the same thing it did the evening before - back became very bouncy, no warning message but rear suspension low (wheel arch over the tyres). Again came back up when I stopped and started and pressed the suspension up button. I could hear the compressor kick in so that seems to be working.

The car was not used from Thursday to Tuesday due to the issue, during which time the suspension stayed up where it should, so it seemed the issue isnt a leak on any of the air springs. Similarly, when I switch the car on on Tuesday to take to get fault codes read, I didnt hear the compressor kick in.

On the way to the garage (less than 5 mins from home) the dash warning message to stop again came on and this time the rear suspension definitely dropped right down. Again, though, when I pulled in and pressed the raise suspension button, it came back up and was fine for the remainder of the 8 mile drive to the garage.

The code reading didnt give any errors for the rear which is what has been dropping. Apparentlly there were codes for out of range for both front sensors and also an error for the compressor taking too long to raise the height.

Based on the symptoms, and that the compressor seems to be working and raising the car, and that it is an intermittent issue, my conclusion (before error codes read) was that it was either a sensor issue - system thinking rear is too high and dropping the rear, but doesnt pick up the change and therefore keeps trying to drop it. However, the fact that the error codes dont indicate a problem with the rear suggests that is not right. The other possibility was that it was a discharge valve sticking open - the system was maybe opening a valve to lower the suspension and that was sticking, leading to the read dropping completely. That would then lead to the compressor taking to long fault as it would be trying to bring up but the air put in goes straight out. However, the fact that the car was not warning when the system was too low the first 2 times it happened would suggest otherwise, unless, of course, it is both.

The technical info which the guy at the garage has managed to get apparently points to the compressor leaking somewhere but I cant quite get that unless, I guess, there is a valve sticking open which is allowing air to feed back from the rear springs and causing them to drop.

After it was looked at it was OK for a day and then it gave the stop warning again but this time it was the front which had dropped not the back. Got the codes read again next morning and the same three as before were there (cleared them before). It happened afew more times since then to both the front and the back separately both never at the same time. Each time when the car is switched off and back on I get the car rising message and it comes back up within the time frame you would expect bearing in mind that it is completely filling two bags 30 secs or so.

The fact that it is switching from front to back leads me to conclude that it cant be a leaking air bag or supply line, and there is no reservoir - the compressor connects direct to the valve manifold. The only common outlet for the air bags is therefore the discharge valve and I am therefore concluding that this must be staying open beyond where it should, either because it is stciking or because the controller is holding it open longer than it should, The compressor is then taking too long to refill due to that valve being open. What I cant reconcile with that is fault codes on the two front sensors.

I am thinking this is one of those issues that if someone has seen the combination of symptoms before they might be able to help.

If anyone has any thoughts with logic to link it with the symptoms I would be very grateful. If you agree with what I say which would you lean towards - the valve or the controller (apparently although the valve is a separate part connected to the compressor it isnt available as a separate part so would need to replace the whole compressor even though that seems to work OK.

I have also read somewhere that there can be a leak inside the valve manifold but cant see that is the issue here and the car does not drop when left standing but again if anyone thinks this could be the issue please let me know how that would cause this.

Thanks
 
I had to have my 2016 50k miles S205 recovered to dealers earlier this year as car went down on all 4 corners and was not drivable. Mobile recovery (RAC) did a code reading showing compressor cut out after running longer than system allows. Car went off on flatbed to dealer. Call later that day car fixed was compressor at fault so new compressor and it’s relay fitted. Even though car was a year out of warranty MB chipped in with 50% of the cost so just over £300 to pay. Picked car up and drove home keeping to the 50mph speed limit. 20 miles into journey yellow warning vehicle low and ride went hard, slowed down to 30 mph and continued. Three miles later and only 1/2 mile from home the dreaded red stop car warning came on. Called dealer who arranged for another rescue. I discussed possible fault suspecting the valve unit as the car had a new compressor and that all 4 corners failed so unlikely to be the air bags. Dealer said the new valves rarely fail ( EBay has plenty of replacement parts for sale so there must be a market for them).

The following day car was ready for collection so went and collected it. Discussed fault which was apparently a faulty replacement compressor so a new one and it’s relay fitted. I asked if the valve block had been changed and was again told no need as the new design is reliable. I said it was a good job they had two compressors in stock the service manager said we have done a number of them. As MB parts have a warranty no charge for the replacement part or labour. Drove home expecting to have problems again but all well and no problems in the last 5 months despite the car sometimes not moving for over a couple of weeks.

So what did I learn? W205 airmatic compressors fail at low miles, QC on replacement parts suspect, overheating or stuck compressor may blow a high amp fuse and relay, the valve block is separate from the compressor.

What could cause the front end to go down some times and the rear at other times? Faulty valve block? Faulty airmatic electronics box? Sticking compressor relay, sticking pressure relief valve, damaged/ corroded wire from level sensor(s)? Without fault codes swapping out parts could prove very costly. The relay will be about £40, valve block £70, electronics box £300? Then labour on top. Sorry to ramble on I hope you get sorted.
 
I had to have my 2016 50k miles S205 recovered to dealers earlier this year as car went down on all 4 corners and was not drivable. Mobile recovery (RAC) did a code reading showing compressor cut out after running longer than system allows. Car went off on flatbed to dealer. Call later that day car fixed was compressor at fault so new compressor and it’s relay fitted. Even though car was a year out of warranty MB chipped in with 50% of the cost so just over £300 to pay. Picked car up and drove home keeping to the 50mph speed limit. 20 miles into journey yellow warning vehicle low and ride went hard, slowed down to 30 mph and continued. Three miles later and only 1/2 mile from home the dreaded red stop car warning came on. Called dealer who arranged for another rescue. I discussed possible fault suspecting the valve unit as the car had a new compressor and that all 4 corners failed so unlikely to be the air bags. Dealer said the new valves rarely fail ( EBay has plenty of replacement parts for sale so there must be a market for them).

The following day car was ready for collection so went and collected it. Discussed fault which was apparently a faulty replacement compressor so a new one and it’s relay fitted. I asked if the valve block had been changed and was again told no need as the new design is reliable. I said it was a good job they had two compressors in stock the service manager said we have done a number of them. As MB parts have a warranty no charge for the replacement part or labour. Drove home expecting to have problems again but all well and no problems in the last 5 months despite the car sometimes not moving for over a couple of weeks.

So what did I learn? W205 airmatic compressors fail at low miles, QC on replacement parts suspect, overheating or stuck compressor may blow a high amp fuse and relay, the valve block is separate from the compressor.

What could cause the front end to go down some times and the rear at other times? Faulty valve block? Faulty airmatic electronics box? Sticking compressor relay, sticking pressure relief valve, damaged/ corroded wire from level sensor(s)? Without fault codes swapping out parts could prove very costly. The relay will be about £40, valve block £70, electronics box £300? Then labour on top. Sorry to ramble on I hope you get sorted.
Thanks. All the parts are pretty accessible to should take too much time to do. The fault codes are not very helpful to diagnosing the issue. I know if I take it to Mercedes their "technicians" (aka fitters) will just throw parts at it at my expense and not actually get to what the issue is but "fix it" by replacing everything with a ridiculous labour charge on top of a premium price for the part so I am not rushing to take it to them.
 
Thanks. All the parts are pretty accessible to should take too much time to do. The fault codes are not very helpful to diagnosing the issue. I know if I take it to Mercedes their "technicians" (aka fitters) will just throw parts at it at my expense and not actually get to what the issue is but "fix it" by replacing everything with a ridiculous labour charge on top of a premium price for the part so I am not rushing to take it to them.
Hi there,

Having a similar problem to this and wondering how you resolved it in the end? In with mechanics at the moment and they can't figure out what the problem is (neither compressor or leak issues). The airmatic failed twice (car sat on top of wheels with warning message) but was seven days between incidents (both on school runs). School runs completed successfully outside of this.

First time all four sides went down and second time only rear went down. On both occasions was able to get moving fully again (car raised to normal levels) after about 10/20 minutes of being parked by the side of the road.

Because issue only rarely happens garage cant get it to repeat!!
 
Wonder if anyone can provide some suggestions for the cause of my suspension problem

I have a C350e which is 4 1/2 years old. DOne just over 60K miles

2 weeks ago when driving the children home from school the back end suddenly became very bouncy. No warning message on the dash board. I pulled over and checked and the suspension was right down on both back wheels. Looked fine on the front. I got back in the car and switch the ignition back on and it came up vehicle rising on dash display. Suspension came back up to normal level and drove home fine. I went out it in later in the evening and was all fine.

Next morning, on the way to school, got a dash message stayin STOP VEHICLE - VEHICLE TOO LOW. Before I had a chance to pull over that disappeared and when I did pull over (maybe a minute later) The rear and front suspension looked fine. Even when the message was on the car drove fine leading me to think that it was a false warning but I dont know for sure.

On the way home from school that evening, it did the same thing it did the evening before - back became very bouncy, no warning message but rear suspension low (wheel arch over the tyres). Again came back up when I stopped and started and pressed the suspension up button. I could hear the compressor kick in so that seems to be working.

The car was not used from Thursday to Tuesday due to the issue, during which time the suspension stayed up where it should, so it seemed the issue isnt a leak on any of the air springs. Similarly, when I switch the car on on Tuesday to take to get fault codes read, I didnt hear the compressor kick in.

On the way to the garage (less than 5 mins from home) the dash warning message to stop again came on and this time the rear suspension definitely dropped right down. Again, though, when I pulled in and pressed the raise suspension button, it came back up and was fine for the remainder of the 8 mile drive to the garage.

The code reading didnt give any errors for the rear which is what has been dropping. Apparentlly there were codes for out of range for both front sensors and also an error for the compressor taking too long to raise the height.

Based on the symptoms, and that the compressor seems to be working and raising the car, and that it is an intermittent issue, my conclusion (before error codes read) was that it was either a sensor issue - system thinking rear is too high and dropping the rear, but doesnt pick up the change and therefore keeps trying to drop it. However, the fact that the error codes dont indicate a problem with the rear suggests that is not right. The other possibility was that it was a discharge valve sticking open - the system was maybe opening a valve to lower the suspension and that was sticking, leading to the read dropping completely. That would then lead to the compressor taking to long fault as it would be trying to bring up but the air put in goes straight out. However, the fact that the car was not warning when the system was too low the first 2 times it happened would suggest otherwise, unless, of course, it is both.

The technical info which the guy at the garage has managed to get apparently points to the compressor leaking somewhere but I cant quite get that unless, I guess, there is a valve sticking open which is allowing air to feed back from the rear springs and causing them to drop.

After it was looked at it was OK for a day and then it gave the stop warning again but this time it was the front which had dropped not the back. Got the codes read again next morning and the same three as before were there (cleared them before). It happened afew more times since then to both the front and the back separately both never at the same time. Each time when the car is switched off and back on I get the car rising message and it comes back up within the time frame you would expect bearing in mind that it is completely filling two bags 30 secs or so.

The fact that it is switching from front to back leads me to conclude that it cant be a leaking air bag or supply line, and there is no reservoir - the compressor connects direct to the valve manifold. The only common outlet for the air bags is therefore the discharge valve and I am therefore concluding that this must be staying open beyond where it should, either because it is stciking or because the controller is holding it open longer than it should, The compressor is then taking too long to refill due to that valve being open. What I cant reconcile with that is fault codes on the two front sensors.

I am thinking this is one of those issues that if someone has seen the combination of symptoms before they might be able to help.

If anyone has any thoughts with logic to link it with the symptoms I would be very grateful. If you agree with what I say which would you lean towards - the valve or the controller (apparently although the valve is a separate part connected to the compressor it isnt available as a separate part so would need to replace the whole compressor even though that seems to work OK.

I have also read somewhere that there can be a leak inside the valve manifold but cant see that is the issue here and the car does not drop when left standing but again if anyone thinks this could be the issue please let me know how that would cause this.

Thanks
I am experiencing the same issue, while driving the car is getting lowered.
Have you got it fixed? What was the resolution for this fault?
 
Hi tigerbenz,

Meant to post an update on here for others. You will see the nature of my issue from the beginning of December. I had the relay replaced and that seemed to do the trick. However, over a week after having the new relay installed the fault reoccurred. Sourced a new compressor pump from Germany (from Miessler), which arrived to me in Dublin less than 24 hours after ordering. Got it installed before Christmas and no issues since.

If your issue is the same/similar as mine, you could try replace the relay first (You should be able to get a new one for less than 20 pounds) and see if that works. Or you could install a new relay and compressor together (the more expensive option). When changing a compressor pump, you must also change the relay.

Very happy with the excellent service from Miessler Automotive when ordering the compressor pump. They answered any queries very promptly and I couldn't believe it arrived so quickly.
 
Hi tigerbenz,

Meant to post an update on here for others. You will see the nature of my issue from the beginning of December. I had the relay replaced and that seemed to do the trick. However, over a week after having the new relay installed the fault reoccurred. Sourced a new compressor pump from Germany (from Miessler), which arrived to me in Dublin less than 24 hours after ordering. Got it installed before Christmas and no issues since.

If your issue is the same/similar as mine, you could try replace the relay first (You should be able to get a new one for less than 20 pounds) and see if that works. Or you could install a new relay and compressor together (the more expensive option). When changing a compressor pump, you must also change the relay.

Very happy with the excellent service from Miessler Automotive when ordering the compressor pump. They answered any queries very promptly and I couldn't believe it arrived so quickly.
Thank you for the quick response, I have extended warranty and believe this is covered under warranty.
Trying to fix the issue through the warranty.
Many Thanks for your detailed information and raised the issue on this forum.
 
No problem tigerbenz.

I believe that this should be fixed by MB under warranty (based on my internet research over the past month!). From what I understand the Wabco compressors originally fitted have a fairly limited life and this is known to MB.
 
I had a sizeable contribution from MB for my replacement compressor a year out of warranty. It is telling when the dealer has several in stock in their parts department.
 
I had a sizeable contribution from MB for my replacement compressor a year out of warranty. It is telling when the dealer has several in stock in their parts department.
Hi Farmer Boy, was your warranty with Mercedes or third party. I’m having the same issue with my C250 2015. It drops in pairs, either front or rear. More often rears. I have to start the engine a few times and eventually is lifting and then I can drive it with no problems. I’m having it booked in at my local dealer next Friday. Have you had it repaired by the main dealer? Thank you
 
Hi Farmer Boy, was your warranty with Mercedes or third party. I’m having the same issue with my C250 2015. It drops in pairs, either front or rear. More often rears. I have to start the engine a few times and eventually is lifting and then I can drive it with no problems. I’m having it booked in at my local dealer next Friday. Have you had it repaired by the main dealer? Thank you
Hi Turbowatcher,

Did you get this fixed?

I've got an intermittant problem of the rears dropping half-way or at my destination. Sometimes re-inflates when turning the ignition and sometimes re-inflates whilst driving.

Thanks
Mark
 
Hi Farmer Boy, was your warranty with Mercedes or third party. I’m having the same issue with my C250 2015. It drops in pairs, either front or rear. More often rears. I have to start the engine a few times and eventually is lifting and then I can drive it with no problems. I’m having it booked in at my local dealer next Friday. Have you had it repaired by the main dealer? Thank you
Sorry completely missed your posting. The repair was 4 months out of the manufacturers warranty. I did not take out the extended MB warranty as it was expensive for what it covers, lot of electrical stuff is exempt from cover. Instead of the warranty I put £50 a month away. The car is now 7.5 years old and has needed: new battery and auxiliary battery ( lockdown none use killed them) and two front airmatic struts ( due to oil leaks not the airmatic bit) so all in all about £2,900 so just over my £50 a month that I put away.

Back to your question the car was out of warranty but MB stumped up as evidently it’s a common problem for water damage to the compressor. The dealership parts department keeps a stock ready. I have always had the car serviced at the same dealership from new but purchased new the car from another dealership using a broker who found me a good deal.
 
Sorry completely missed your posting. The repair was 4 months out of the manufacturers warranty. I did not take out the extended MB warranty as it was expensive for what it covers, lot of electrical stuff is exempt from cover. Instead of the warranty I put £50 a month away. The car is now 7.5 years old and has needed: new battery and auxiliary battery ( lockdown none use killed them) and two front airmatic struts ( due to oil leaks not the airmatic bit) so all in all about £2,900 so just over my £50 a month that I put away.

Back to your question the car was out of warranty but MB stumped up as evidently it’s a common problem for water damage to the compressor. The dealership parts department keeps a stock ready. I have always had the car serviced at the same dealership from new but purchased new the car from another dealership using a broker who found me a good deal.
Many thanks Farmerboy.
 
Hi Turbowatcher,

Did you get this fixed?

I've got an intermittant problem of the rears dropping half-way or at my destination. Sometimes re-inflates when turning the ignition and sometimes re-inflates whilst driving.

Thanks
Mark
Hi Mark, yes I did. I had warranty 3 months from the dealer i purchased the car from, RAC cover and they have covered the cost. The compressor needed changing. Mine is 65 plate. The legs were ok not leaking. It wasn’t raising either front or rear. I changed the fuse a few times, £2 at Halfords for a 40amp fuse orange and it was working for a bit. Then dripping again with the message Malfunction. In the end it did not lift at all, had the message vehicle too low, do not drive vehicle. Took it to the main dealer and they have replaced the compressor at a cost of £890. The warranty covered only £758. It’s been fine ever since. I now have another issue, the adblue indicator is showing empty but 6000 miles range. Tried to top up and spilled all over. Doing my heddin so far but no messages so I will leave it alone. Hope this helps. Regards
 
Loads of post/threads on here about the poor Adblue system on Mercedes and the problem therewith. Sadly most end up advising owners to chop them in for petrol models ASAP or at least before the warranty expires!!!
 
Loads of post/threads on here about the poor Adblue system on Mercedes and the problem therewith. Sadly most end up advising owners to chop them in for petrol models ASAP or at least before the warranty expires!!!
What, to sell it and buy petrol? No way! I have 3 years warranty on it so they will have to replace the pump and the tank of it comes to it. So fragile these cars, you would think it’s a Mercedes. They are so poorly built.
 
Guys my w205 2015 rear suspension has dropped twice in space of a month overnight.. when I start the engine it raises itself back up ok and then no issues whilst driving.. could this be needing a new compressor?
 
Guys my w205 2015 rear suspension has dropped twice in space of a month overnight.. when I start the engine it raises itself back up ok and then no issues whilst driving.. could this be needing a new compressor?
More likely is a strut that needs checking rather the compressor. If it was a faulty compressor then the car wouldn’t raise at all.
 
More likely is a strut that needs checking rather the compressor. If it was a faulty compressor then the car wouldn’t raise at all.
Ok so both rear struts? I have warranty with the independent seller so will get them to have a look..
 
2016 C350e: Similar intermittant Airmatic issue- rear left corner drops randomly whilst parked, rear right corner as well, but not so much. It is very intermittant- away on holidays for 10days & return to airport car park- levels are fine. Yesterday park the car in the driveway & a few hours later the rear is down. When I start car get the "Vehicle is rising" message & the car is pumped up again & all is fine. I had a new MB compressor fitted by my indie MB mechanic in Jan '22, so my first instinct/hope is that perhaps the compressor pressure relief valve is faulty? But if this was the case would all 4 corners not be down? At least if this is the issue the MB compressor has a 2yr warranty(?) so hopefully the mechanic would get a free replacement, but would probably still charge for his labour. Maybe a Rear Left Air Bag leak, which is what the indie MB mechanic said over the phone, going on the info that it was that corner only- but then why would it happen intermittantly & not every time I park? Otherwise- valve block leak? Rear distribution block leak? Air line leak?

Is it best just to jack the car up, remove front left & rear left wheels, front left wheel arch liner & try leak testing as much as possible?
 

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