Hi somewhere on OBD Eleven should be an adaption facility this trains the new unit to learn its values again via the ECU which then thinks ok the units new and cancels the old learned values and starts to re learn its new operating strategy, it can be left and will work it out itself but I have always found the re adaption method cancels any funny running while it learns, your type of valve is not dissimilar to mine and they normally fail because the valve in the cut out leaks excess gas into the engine, nowadays thats known as excessive EGR flow.
Steve.