I have 05 Volvo V70 2.5T, a month ago it started a surge when it was idling at 650 rpm then down to 550 rpm then return to 650 rpm. So I went to to my local auto parts and used their OBC II and it came up with what I put in the title of this message. Well I tried erasing it a few times but kept coming back, so I ran everything in the OBC II and it showed "engine oil level at 79.69%" and pointed to the "NOx/SCR EGR/VVT 02 SENSOR/HEATER MONITOR" and most likely it's the upstream 02 sensor and a oil change and fill the tank and add Sea Foam oil & fuel treatment. It should cost less $100 for 02 sensor, Sea Foam oil & fuel and a oil change I use Castrol Edge Full Synthetic 5w30w, but you use any oil you choose.

 

Are you talking about a 2005 or 2015? Not sure a 2005 will report the engine oil level. As far as adding Seafoam to the fuel, its a detergent so the implication is you cleaned a dirty injector. Running a premium brand 93 octane will also have detergents so unless you have not cared for the car properly adding seafoam to the gas won't really fix anything. Same with the oil. Sadding Seafoam to the oil can clean out oil galleys and perhaps free up a sticky VVT but it can also loosen sludge that winds up in your PCV pipes. Its a pretty agressive treatment for a gunked up engine and should only be done just prior to an oil change or planned service to the PCV. Castrol Edge is a top shelf product - I also use that for my car but for my 2000 S40 I use a full synthetic with seal softeners. Note you can use any premium brand full synthetic that meets Volvo's oil requirements specs (found in the owners manual or on websites like bobistheoilguy or amsoil).