Ever Since I had my engine replaced, the SAI has not turned on when the car starting cold anymore. I have zero codes and I just thought it was weird. Should I be concerned?
Under Engine in VCDS, click readiness. It will show the current status of the bits. Then go into fault codes, and clear codes. This will reset readiness to not tested. Then check the status again. If Secondary Air injection says Passed, then your tune is messing with the emissions components.