I wanted to share with everyone a tip that I have used on several older Volvo models to take care of fault codes in the PCM.

These codes generally point to a mass airflow sensor but very little can ever go wrong with those. The occasional cleaning will usually take care of these for the life of the car.

Cleaning the throttle body (both sides) can get rid of codes and erratic idle problems. The engine computer sees a lack of airflow due to blockage around the throttle blades requiring that the blades open wider to get airflow.

The only way to clean a throttle body properly is to remove it and clean both sides, plus the edges.