Recently I reported replacing the 556 ECU in my 1992 with a used 561 that came out of a 1991 240. Works great so far, but I recalled some mention here that the 561 was trouble. I looked through the archives and found a couple of brief comments but no true skinny.

So, let me ask:

1. Is it true that the 561 has a bad reputation? If so, does it tend to croak suddenly, leaving one sitting on the Interstate?

2. Is the 951 a direct replacement--and if so, what cars/years would normally have a 951?

Thanks for any help you can provide.

Doug Harvey

Matt is right. I'll add that at one tiome inferior solder in the low-wage country of origin was thought to be the problem. I'll also add that you can check 89-93 240s and normally aspirated 700 (900?) cars for the 951.

Is there anything saying you can not change say an old 544 to one of the latest ECU models? The system is the same, but ign is differnt. Also, could swap out an 007 to 016 AMM.

Just wondering seeing how I have both of each as spares for my cars which span from 86 to 93.

dick
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93-940T + 91-940SE + 87-740GLE = One Happy Volvo Garage!

The 561 was in fact defective with respect to long-term reliability. In my experience it can fail in any number of ways, I have not seen them fail suddenly on the interstate, but I have heard of people being 1000 miles from home and suddenly the car won't start, or they can die a slow death, where idle becomes rough and erratic, gas milage gets progressively worse, performance sucks, etc. The 951 is a direct replacement and seems to be reliable.

Look around on ebay or talk to brian@volvousedparts.com to find a good 951 for around $100-$200, and carry it around with you as a spare. Most 561s have already failed by now... so you're probably on borrowed time.



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Matt L. -- Cary, NC -- '91 740 wagon