I received my upgraded ECU on 3 July for my 1998 V70 T5, Manual 5-speed. I installed it and headed out to the Interstate for a test run. From a 25 MPH roll in second gear, I firmly pushed the pedal to the floor.

I watched the RPMs rise quickly.
I watched the MPH rise quickly.
I watched the boost go above 10psi (like never before) and quickly dance around 14 PSI.
I felt the waste gate open and the power fall off (no surprise there).
I watched the "CHECK ENGINE" light illuminate (Big surprise there) and remain illuminated.

Repeated the same process today; same result, but this time the "CHECK ENGINE" light flickered a bit before remaining lit.
I suspected that I was piling fault codes on top of fault codes.
I do not have an OBD-II Code Reader, but I was due for a service anyway, so will let my mechanic tell me what the codes were.

More to the point, is this a typical scenario right after an upgrade? I would hate to think that I would have to deal with a "CHECK ENGINE" light every time I go into the higher boost ranges.

Any ideas out there in Brickland?
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Dave in Virginia; 98 V70 T5(M); 98 V70; 88 245 DL; 67 MGB