What do the codes P0171 AND P0172 mean in a 1998 Volvo S70?

The codes P0171 and P0172 for a 1998 Volvo S70 indicate issues with the air-fuel mixture. P0171 signifies a lean condition, meaning the engine is getting too much air or not enough fuel, while P0172 indicates a rich condition, meaning the engine is receiving too much fuel or not enough air. These codes can result from various issues, including vacuum leaks, faulty fuel injectors, or malfunctioning sensors like the mass air flow sensor. Diagnosing the exact cause usually requires further investigation of the vehicle's fuel and air intake systems.