When you find the answer, Please let me know!!!!
Seriously, I am on my second ECU, the current one I bought used for $100 from a scrapyard, which is giving me the same problems that I had with the first one after only a year and a half (orig lasted 230k, now at 255k miles).
Things that I have learned about the Bosch XXXX561:
1. It is the only one that can be used on the 240 with a 5-speed. Automatic's don't work which are easy to find and cheap.
2. Volvo made an upgrade replacement for a lot of $$'s. I haven't found a re-built for less than $700
3. When it goes bad the speedometer and upshift light stop working along with idle control. Sometimes the engine cuts out completely.
4. I tried a '94 940 B230F automatic ECU but the speedometer and upshift light didn't work. On the 5-speed, the speedometer sender and crank sensor feed into the ECU to operate the upshift light. When they fail the car usually has idle and or acceleration/deceleration erratic behavior because the fuel is controlled to match engine speed and load to improve fuel mileage.
5. I curse Volvo for the damn 561, and am about ready to drop in a '78 rebuilt 242GT motor with CIS and scrap the LH 2.4 Jetronic.
6. When it works, the system is the best of the 2.4's. I get near 30 mpg. I had a '92 245 automatic that was slow and unresponnsive and got 22 mpg at best.
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'89 245 Sportwagon, '96 960 sedan