Hello All.
How do I know if my EHA valve aka Idle Valve is working properly on my 85 190E? Please let me know if I can perform a test! Thanks all!

First, the EHA and the idle valve are different items. Which do you want to test?

Second look to the article in the DIY section on evaluating engine controls. The test methods are explained using generic test equipment.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Hi Steve..
Thanks for your reply. I think it is the Idle Valve that I need to test. Its the one with the plastic adjustable screw beneath it that adjust the flow of air! I had some rough idling problems with my car.. I played around with the little screw and my problem is gone now. But it would come back once in a while (interminently). I cut electricity going to it)!!! And it did not make any difference as far as idling and engine performance. So I am guessing that the idle valve is not functioning properly, or not functioning at all! So your help will be appreciated!