Well, things are NOT going my way. I'm aware that my 10% DVM reading is equivalent to MB 90%. Their shop manual says "unused--no fault code" for a 90% reading. I got my new ebay ECU today and hooked it up. The initial signs were great. Had current at EHA that was in spec (around 13 mv cold I think). It started up much better and came up to idle for a minute or so, then reverted to old low idle. I had the O2 sensor disconnected, so figured that was the issue (I understand the engine runs open loop for a short time after startup). Shut car off, reconnected sensor, started and was back to the old "normal". Then checked EHA current again and it was zero. Voltage at air sensor was essentially zero too vs spec of 5V. Put old ECU back in and now the air sensor is at 5V regardless of sensor position. I think it is blown. One thing that could have been a factor in all this is that I started the car using a remote battery. It was out of the car and I used jumper cables to connect to the battery cables. It cranked very slowly and stopped cranking a few times like when your battery is almost dead. Could this damage the ECU or other electronics? If so, some engineer at MB should have been fired! I did NOT reverse the battery cables at any time. I rechecked the OVP relay. I'll be returning the ECU and hope my air sensor isn't blown. BTW, I did the circuit board cleaner on my old ECU with no effect. It was replaced in 1999 if that is any clue. The 190E is a really nice car, but I bought it to DRIVE, not to work on for 100s of hours! I'll be checking the wiring harness (again) but my big question is will low voltage on cranking damage the ECU or air sensor?