Hi, I own a 90 2.0L 16V (Motronic) Jetta and I am wondering if a 16V Passat ECU will work in my car? I know of a few local junk yards that have some wrecked early 90's Passat's.
My ECU code is Bosch# 0 261 200 858 and VW# 8A0 907 404 C C sound common?
The reason I'm replacing the ECU is because I figure it's fried due to the main ECU ground post on the rear of the head being badly corroded. (found that out a little to late!) The car has been working like crap, and before it finally quit I noticed that it was sort of surging? At idle the lights would dim and the Alt. would go under load (belt would start to slip) for a few seconds then it would come out of it? The Bentley says this is a sign of a bad ground. I removed the Alt. and took it to my local parts store to have it checked and they said it was no good. Being under warranty they gave me a new one for free, but it also came up no good on their tester. I took it anyway and am going to have it checked else where. I think their tester was faulty, but I got a brand new Alt. out of the deal!
Before I blamed the ECU I did all the tests in the Bentley, I was getting no spark so one of the tests said to connect a test light between #2 and #3 of the power stage. It should have flickered when the engine was cranked but did not. It then said to check the continuity between #2 and #11 of the ECU, that was fine. So then Bentley says the ECU is bad. I still didn't want to believe that so I did all the checks in section 5 which checks all the inputs to the ECU, they were all fine except for one. There is a break in the wiring in my Knock sensor #1 which I plan on fixing before the new ECU.
Anyway if anyone has run across the same type of problem please feel free to share some insight.