Cooperate with seller and try to resolve issue before buying. A quick online search yielded
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P0958 Auto Shift Manual Mode Circuit High. when i try to do the shift selector mode, the D for drive flashes and the CEL comes on. i have read that this means i need to replace the pin shift selector switch, part # 35740-SEC-A82.
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There can be other reasons for this error as well. More details on this thread. Try to identify the exact sensor causing issue first.
https://acurazine.com/forums/3g-tl-problems-fixes-114/check-engine-light-d-light-blink-code-p0816-p0958-930462/
Do some online search on Acura tsx forums and I think you can resolve the issue. But resolve it before buying the car.