Air Ride Suspension Trouble.

T

Too Many Cars

Registered
It has been a long time since I have posted on this forum; however I have several problems (hopefully all related) on my 95 MK8. I am not even sure if this is the correct area but here goes.
The car sat for a long time (over a year) and displays these symptoms. The Air Pump doesn't come on at all. The car is sitting about an inch lower (I think from memory) than park height (definitely not slammed) at all four corners (not too bad for sitting so long I guess). I DON'T get an air suspension error message so I doubt the problem is the relay. I tried the self test for the air suspension and nothing happened. It almost seems that the Air Suspension computer is either dead or it isn't receiving power (maybe fault signal is an active high?).
I do get an ABS error message. Another clue is that my turn signals don't work (bad ignition switch?). I took the car for a ride and it drove OK for a car that needs a front end rebuild (the front end and an oil leak between the oil filter adapter/block when cold) are the reasons for it being parked. Before sitting these symptoms were non existant.
I did a search and didn't see any thread that matched these symptoms. I figure that since the weather is starting to get warm I would look into troubleshooting these problems. Have any of you encountered this/these problems. I tend to think/hope that the problems are symptoms of one problem.
 
As the car sat for so long, first thing I would do is simply turn on the key (but NOT to the start position). Listen for the air pump to come on.... it will prob time out and the air ride error will come on.... turn key off for a few seconds and turn back on. Do this for about 3-4 times to see if the bags inflate. After you do this, let us know what happened.

Turn signals are prob a different problem... check the fuses.

Make sure your oil level is okay before driving car..... or get the new gasket in anyway. That's not a really difficult repair.... use the search function for the how-to-repair.
 
I tried that several times and believe it or not the pump doesn't come on at all and I get absolutely no error message about the Air Suspension. I may go out there today and look for the control module (at least it isn't 20 degrees outside like when I discovered these problems!). I just found a wiring diagram/schematic on another thread. The system doesn't look too complicated. I am thinking somehow the control module isn't getting switched 12 volts or somehow the module died. The oil level is good and it is warm enough outside that it won't leak oil. The oil leak only happens in the winter and only when the engine is very cold.
 
I just had a flashback to my sunroof/headliner incident of a few years ago...

Do *no* turn signals work? or just not the front ones? There's lots of space up inside that front bumper for mouse nests... Could they have chewed through some wires? That might explain the ABS light also..
 
No turn signals at all including the indicators in the dashboard. The reason that there may be a connection between the problems is that they are both totally dead (too much of a coincidence) like neither of the systems seem to be getting power. Unfortunately I took the car off of trickle charge for too long and now the battery is dead so I doubt that I am doing any troubleshooting today. We will see.
 
In normal circumstances I would agree with you; however many problems occured since the car was last driven. Either the car developed many unrelated problems when it was sitting (possible) or one problem is creating several symptoms. I am hoping for the one problem scenario because I don't have a lot of time to devote to troubleshooting this car.

I really haven't started trying to troubleshoot (on the actual car) yet (it was too cold for that until today when I discovered that the battery was dead) but it is puzzleing that the car doesn't air up yet doesn't report that there is a problem. Every thread that I read reported that the car didn't air up and then they got a report of an air suspension problem. When I do a system check the air suspension comes up as being OK even though the car doesn't even try to air up. The emergency flashers that I believe use the same bulbs do work though and I believe that they don't rely on switched 12V to operate. I need to find out where this suspension control module is and do some troubleshooting because so far this doesn't make sense.
 
The suspension module is located behind the passenger side kick panel(cowl) to the right of the glovebox. It has two plugs, one gray and one black.

I would check the fuses first (both underhood and passenger compartment). Then check for voltage at pins 1 & 21 of the black plug for the suspension module. Pins 1 & 21 are hot all the time and pin 4 is hot with the ignition on. See attached pics.
 

Attachments

  • C204.JPG
    C204.JPG
    25.1 KB · Views: 0
  • C204pinout.JPG
    C204pinout.JPG
    35.9 KB · Views: 0
The first thing I would do is get a new battery, then take it from there.

I did some tests on both of my Gen 1's. After about an hour, they both stabilized at a battery drain of about 38 milliamps.

These cars don't like to sit without being driven.:D
 
Problem solved I hope!

Problem solved I hope!

Thanks for all of the info. I will keep all of the images of the module I/O in a directory in case I ever get a real problem with the air suspension.

The problem is solved including the turn signals. The car aired right up on the first cycle which is a good sign a suppose.

I simply had a blown fuse that was common to the turn signals and the air suspension module. I never had any electrical problems on the car so I didn't even know there was a fuse box inside the car. The only thing that bothers me is that the fuse was vaporized indicating that it must have seen a direct short circuit. I hope that I don't have an intermittent short to troubleshoot.
 
Air Bag 15 Amp fuse. For some reason if I pull this fuse I loose my turn signals and my Air Suspension so they obviously have commonality (at least in my car). Maybe as an experiment someone could try pulling that fuse (in the passenger compartment fuse block) and see if they get the same result. I didn't study the wiring diagram so I don't see the connection. I just know the result.
 
I see the commonality now. Further reading show that this fuse does many things including the multi function switch, air suspension, antilock brakes. At least according to this Chiltons that I dug out of the closet. I can't find my workshop CD so I guess that this Chiltons will have to do for now.
 
I hope that I don't have an intermittent short (although looking at the blown fuse it looks like I do!) because this could be a PITA to troubleshoot. Why would they use one fuse for all of those functions?
 
Too Many Cars said:
I see the commonality now. Further reading show that this fuse does many things including the multi function switch, air suspension, antilock brakes. At least according to this Chiltons that I dug out of the closet. I can't find my workshop CD so I guess that this Chiltons will have to do for now.
Click to expand...

Ohhh, THAT fuse... :)

I/P Fuse Panel - Fuse #10 - 15A
  • Multifunction Switch
  • Air Bag Diagnostic Monitor
  • Anti-lock Brake Relay
  • Anti-lock Brake Control Module
  • Air Suspension / EVO Steering Module
  • Steering Wheel Rotation Sensor
  • Transmission Range Sensor
  • Daytime Running Lamps Module
 
You must log in or register to reply here.
Back
Top