Thread: Diagnosing air suspension problem

Check the dryer to see if the desicant is damp and has expnaded?

+1 on that .

If you've got a fault code reader , check pump vacuum fault.

Originally Posted by Tote

Do the lines to the compressor stay at tank pressure or is there another valve?

The pressure in the lines from the compressor to the reservoir valve and the front and rear valve blocks is always dumped as soon as the compressor is stopped, excepting if the exhaust valve is siezed shut!

The compressor should not run for so long. Most likely the vehicle is too slow to raise which causes a fault to be logged.

As well as a possible clogged dryer, the compressor outlet valve could be worn-out, so hopefully its either this or the dryer rather than the compressor itself. With the dryer removed from the compressor, you should be able to blow through the dryer albeit with some resistance. The dessicant can be removed from the dryer and dried in a micro-wave oven. New dryers are available, as well as outlet valves for at least some versions of the compressor.

Originally Posted by Neil P

check pump vacuum fault.

Pressure?

Yup drier is easy to fix. remove compressor and remove drier. Then empty contents into abowl and microwave till dry. Reasemble and it should work.
Just did mine. Now goes up quick and farts properly.

Ok, an update. I fitted a spare compressor that I had put a new exhaust valve in with no real difference in the fault displayed. A couple of observations:
The compressor I pulled out is the current part number and less that 12 months old
The spare compressor is an older one but is noticably quieter running.

I am still experiencing the same symptoms where I will get a couple of suspension faults in the morning and then the vehicle will work fine all day. The number of faults is intermittant and occasionally will occur in the afternoon if parked all day and sometimes I wont get a fault at all that day.

Vehicle is not dropping overnight

When I replaced the compressor after the vehicle had been sitting for a while the hose that connects to the blue connector on the drier was slightly pressurised. I would have thought the pressure would have been vented from this line when the compressor shut down.

BBYER, can you please repost those links on the schematics from the UK forum as I couldnt find them with a search before you posted them.

Regards,
Tote

The noisier compressor is probably the better one but suggests a blocked dryer. Have you removed its dryer and tried to blow through it?

Yep, both driers are easy to blow through with only a small amount of resistance.
Regards,
Tote