Air Ride Troubleshooting List of Categories Thanks to Scott Miller (Avu3) for compiling this info!
Thanks to ekooke for the test procedure using a code reader!
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One end of the car falls to the ground
This is indicative of a leak on the falling end of the vehicle. A sudden drop while driving is typically a catastrophic failure (blow out) and rare unless something happened like hitting a curb, pothole, or other car.
You may also experience a sudden drop while driving over rough roads, or when you flex the suspension a great deal at speed, this is because the leaks in the bags have been exercised and opened up.
Pictures of this are on Eddie's site here:
How to leak test
Check out the last two pictures.
Typically the air strut drops over time (while parked at work, overnight, etc.) This is a slow leak that should be fixed promptly. Failing to fix the leaking bag will result in your compressor having to pump too much air through it (to overcome that lost to the atmosphere) and will fail prematurely.
Instructions for doing this are here:
Strut Replacement Paper
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The car fails to vent, you get a check suspension light but the car is high.
You get a check suspension light at speed on the freeway.
This is because air can’t get out. The system adds air to compensate for loads and to lift the car to driving height. When it wants to remove air (load removed, speed vent on highway), it vents. The vent portion of the compressor frequently rusts closed due to moisture in the system (THIS IS WHY YOU MUST FIX LEAKS PROMPTLY) caused by leaking bags or atmospheric conditions.
The air compressor is located in a tray in the right front corner of the car. You can remove/replace it by either removing the bumper cover and working in front of the tire, or you can remove it by removing the splash shield and working in with the tire.
There are pictures and a discussion of the splash shield method here:
http://www.markviii.org/dcforum/DCForumID13/2178.html
There are discussions of the bumper method here:
http://www.markviii.org/cgi-bin/dcforum/dcboard.cgi?az=read_count&om=409&forum=DCForumID13
http://www.markviii.org/cgi-bin/dcforum/dcboard.cgi?az=read_count&om=148&forum=DCForumID13
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Check air ride light 90 seconds after Key On.
The compressor has hit the thermal limit. It will not run any longer as a fail safe. This is usually indicative of a leak in the system, but could also be a worn out compressor that is not creating pressure. To search for leaks, use soapy water on all the air line connections (one at each wheel, four in the compressor) while the compressor is running. This is usually also accompanied by lower than normal ride heights or recent system service.
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Check suspension light comes on immediately with key on, compressor does not run.
This is usually a power/electrical issue. Quickly rule out the compressor relay by switching with the ABS relay. If this solves the problem, you need a new relay. Also check the fuse. The compressor can work while increasingly drawing more and more power to overcome internal failure, until it reaches the fuse limit. When that happens, you need a new compressor.
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How can I test the Air Ride Function?
You can use a EEC-IV code scanner to run an automated test sequence on the air ride system.
1. Turn ignition on
2. Unplug test plug
3. Plug in reader
4. Flip switch to TEST
5. Tests run automatically
From a post by ekooke, here is the order of testing:
LF solenoid clicked open/close
RF solenoid clicked open/close
Rear solenoids clicked open/close
Compressor vent valve clicked
Compressor ran for a few seconds then shut off
Then the system did a height sensor test:
Compressor turned on, front valves clicked, and the front of car rose, valves clicked then the same thing(s) happened for the rear and the rear rose
Compressor turned off AND; vent valve clicked
Front solenoids clicked & front lowered
Rear solenoids clicked & rear lowered
There was a little clicking after that, but nothing noticeable happened (maybe vent valve).
Original thread here:
Thread about using code reader to test Air Ride
NOTE: There's really no output to the scanner; when the testing hits a fault, it just stops at that point. The operator monitoring the KNOWN testing sequence is what identifies the fault.
If you don't have access to a code reader, user "billcu" posted the following:
If you hold the connector with the open end of the plug facing you, the top row of terminals (from left to right) are pins 1, 2, 3, 4.
The bottom row are 5 and 6.
The wire color for pin 2 is W/LB.
Turn the key on, close the door, connect the test light from pin 2 to battery ground, and let the fun begin!
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