Yes, you should have a CEL and a knock sensor code if it's the plug for them. I'll take a look at my 98 for any ideas as to what it might be.

The 1998 Volvo wiring diagrams are public on the web. We don’t host them here per an agreement with Volvo mothership. We are allowed to link to them here , and that has been done

I think it is listed as 7/95 on the diagram. Here is a picture of mine.

I also use an ELM 327 el cheapo BT dongle for my '98. It's worth reading through my climate nightmare thread here: https://www.matthewsvolvosite.com/forums/viewtopic.php?t=102381 There's a ton of good info and diagnostic aid in that thread when I went through everything in my car to fix my own drive...

I also use an ELM 327 el cheapo BT dongle for my '98. It's worth reading through my climate nightmare thread here: https://www.matthewsvolvosite.com/forums/viewtopic.php?t=102381 There's a ton of good info and diagnostic aid in that thread when I went through everything in my car to fix my own driv...