I have an 02 S80 that I bought used a few months ago. Just recently the oil pressure low light started coming on when at idle and the engine warm. When you apply gas it goes off. I am going to look into the oil pressure switch. I just had the oil changed on it about a month ago and they said that the oil was only slightly dirty. Yesterday the car started running kinda rough. The check engine light did not come on but the P0740 code was stored in the computer. Could the converter controller be what is causing the rough idle? This is my only vehicle and I need help!!!

 

Converter controller? Torque converter? It's what helps gets power to the ground from the engine an tranny.

First off you just had a oil change, check the level. If they didn't run it shortly and add more oil after the filter never got filled and your a little low.

Second yes pushing the gas revs the engine and circulates the oil faster and brings pressure up that's why the light goes out when you do.

Third did they put the right oil in your car? Check what they put and your owners manual.
Volvo doesn't exactly specify the oil they give the types and temps in owners manual that they're good for and you choose based on your climate.

Oil pressure is created by the oil being pushed threw your main bearings. No oil pressure and a bottom end knock means she needs atleast 1 main bearing.

Also, these cars need alot of seals done In the oil pan time to time, 5 total seals. There's a post about it in here, link https://volvoforums.com/forum/volvo-...ructions-1451/