2001 S40 - Erratic Idle;high Idle Rpm(1500);stalling

Answer 1

Use a scanner to read the air count. It sounds that there may be a lean condition that may or may not cause the engine light to come on. This car is very tricky and not for a DIY as you have to be familiarized with how Volvo's operate and have the proper tools. You need a volvo scan tool for just about every system on the car and they do this on purpose. If there is a lean condition it may be caused by an air leak of some kind and you must find the source of the leak. This is what the problem sounds like. Typically there is usually one part that fixes most issues with cars built after 1999.