W220 Pneumatic Pump Vacuum leak?

[Riva811]

Hello,
My trunk (or boot) wasnt opening up and I could hear the pump working non stop. Now it seems that the pump failed and I can only listen to a click when locking and unlocking via the key. The mirrors fold in and the alarm is triggered but the locks dont go down. I can lock the doors from the inside except the drivers door lock which refuses to go down. Also, I am unable to lock/unlock the drivers door using the physical key. So I am wondering could it be a vacuum leak that got me into this mess?
The following do not appear to work at the moment:

• Central Locking
• Trunk
• Soft Closing
• Privacy Curtain at the rear.
• Headrests not dropping

 

[Uky]

If you are lucky, only the fuse is blown. If you are unlucky, the pump itself is gone and they are not inexpenceive.
Second hand units can be found on eBay but then - they may also have a certain "milage". Several different
spare part numbers exist so the exact type in your W220/C215 will have to be established. The pump (mechanics)
itself may be intact in which it is possible to replace the electronics or the other way around, but that is only for
people with plenty of time (and luck).

Normally when there is a leak, the pump will work for a certain amont of time after which a time-out occurrs.
If the fuse blows, the pump and/or the electronics is gone. For a W220/C215 with everything else in fine condition
I would go for a new pump altogether. My old C215 needed a new pump after 10 years.

When checking for a leak, the MB mechanics have a special tool that looks like a pistol
with a pneumometer. One by one the air hoses are checked. It is impossible to do this using your lungs
and any serious attempt will result in a stroke...

One common failure is the hoses that goes to the front seats. If you are lucky, the hose has come loose
underneath the seats (Not to uncommon when vacuuming the car) which is easy to fix. If you
are unlucky, there is a Y-splitter underneath the carpet and both seats will have to come out.
Or - it can be the pneumatic bag inside a seat.

If you intend to make a thorough investigation yourself I would disconnect the battery
since any attempt to use keyless or to put the car in ignition state 1 if the
seats are out of the passenger compartment will immedately trigger a SRS DTC
since the SRS loop will be opened. Such a a DTC can only be reset by a workshop with Xentry.

 

[Riva811]

Thanks for your response. I was quoted £678 for a brand new pump. Then this mechanic suggested we can just replace the motor inside the pump. Car is not in the UK and local dealerships charge even more (I think they replace the price currency symbol and then multiply by 2 ). I dont have any tools with me so I am going to rely on him. The car doesnt have keyless go option.