My 1990 240, automatic, sedan has 136K miles. At about 100K, 3 years ago, I had an independent Volvo guy replace the ECU due to catastophic failure. He put in a remanufactured 561 unit. For the last few weeks the car has developed a fast idle. Otherwise the car is fine. The independent Volvo guy says the 2nd ECU is now bad. I trust him since he done good work before. I told him that i would try to find a used unit before spending another $700.00 for a Volvo re-manufactured ECU. He cautioned me that I should only use a 561 unit; any other unit might damage things. I have a few questions if somone would be so kind:

1. Is there an alternative ECU that may be more reliable? I remember something about a different unit number, perhaps 951. Can anyone confirm that this would be OK?

2. I believe that the ECU is mounted behind the passenger kick panel in front of the door. Am I correct? Ho do I remove this panel and other items to get at the unit?

3. Does anyone have an ECU for this car that they would like to sell? If so, how much?

Thank you for your time.