Funny problem perhaps someone can help:
I had all for air suspension shock absorbers replaced with Billstein units. And I put in an overhauled compressor. Got the car back from the shop, everything works fine except one thing:
I get an CATS failure with amber light for a tenth of a second and again and again. Was hard for me to identify because of the short duration of time the fault lights up. As I say: goes on for a thenth of a second and then off again. Half a mile down the road same thing. Tends to get better on longer drives. Once I park the car for a couple of minutes same thing.
I examined with Code reader: nothing. Only the ominous P1000 code.
Anyone have an idea what that is and if I have to do something.

 

My first thought was to suggest looking at what code was being set... that is going to be a tough diagnosis without some direction as to what is flagging the fault. The CATS system is monitoring the solenoids in the shock absorbers. If any of the 4 coils is open, shorted, or shorted to ground, the system will flag an CATS Fault and default the shocks to hard mode.

If you had no CATS issues prior to the new air springs, then one of the new shocks is the most likely culprit. You could start by checking the electrical connectors to the top of each shock. If they are secured and no signs of corrosion, then check the resistance of each shock solenoid coil. See if there is an outlier. Also check from each coil to body ground (there should be no path to ground).

 

+10
I agree! There is an intemittency somewhere in electrical curquit of solenoids. Very probable crimp connection to wire on harness side. There are muliple ways to troubleshoot it including attaching proper resistor to harness side of connector to trace which particular connector out of 4 causing an issue.
But then again, shop will figure it out. I am surprised they did not fixed it before handing you key to the car!
At least should have told you what they have eliminated as possible problem.

 

Thank you very much for your competent replies.
Yes I totally agree with your assessment. Since it is such an extreme short time failure I would go for a contact problem in one of the plugs. So I will remove them, perhaps apply a bit of contact spray to overcome corrosion and reseat them. The corrosion problem should be evident on a car that has 230.000 km on the clock.
I am really grateful for your replies