Every so often the ADS warning light in the instrument cluster goes on, red LED on switch lights up, and the ride stiffens, especially the rear suspension. Hardly ever happens with a cold engine, but switch on the engine when the car is still in operating temp and its almost a given to light up. Then it goes out after a while or stays on for the whole trip.

Off to the local dealer then! Car was hooked up to the computer, no fault codes related to the ADS. The ADS warning light in the cluster wasn't on at the time. We hooked it up again, this time while the ADS warning light was on, and the diagnostic computer couldnt establish a connection with the ADS control unit.

So, whenever the ADS warning light is off, the diagnostic computer has no trouble connecting and reading the ADS system and no faults are ever found. ADS warning on - cant read ADS computer.

Inspected the suspension visually for system leaks. Car has new air cells, new hydraulic oil to the correct level, and was bled properly. The harness leads were disconected and re-connected and sprayed with contact cleaner for good measure. Battery voltage tested and normal.

Diagnosis is a faulty ADS ECU, but I'm not so sure since it's such an intermittent problem. I dont wanna replace a $$$ part and find the problem still there! Any suggestions? Anyone with any experience on this? Please help!

BTW, car is a 1997 E50 AMG. Thanks!!!