I brought my 2005 S40 in for its 7500 mile service. A couple of days later the check engine light came on. To be safe I wanted to check the oil to make sure the tech. put oil in the car. When I popped the hood the dipstick was laying on the side firewall of the car, apparently the tech forgot to put it back into the car. Would the lack of an oil dipstick trigger the check engine light. I was thinking maybe it caused lack of vaccum or the pcv valve was not reading pressure so it triggered the check engine light. The light went off 2 days after reinserting the dipstick. Also the oil level was at the bottom line of the safe zone of the dipstick. What is the recommended level? Any input will be appreciated. Thank You. Lee

 

I would try to put a little oil in it.The Safe is fine I like to keep it in the middle of the lines.

I doubt that will turn the light on but it is possible.