My 98 V70XC AWD w/140K miles has a CEL and the codes pulled are P0130 Sensor Circuit Malfunction (Bank 1 Sensor 1) & P0135 O2 Sensor Heater Circuit (Bank 1 Sensor 1). I reset them but came back 2-3 days later. I think this is the O2 sensor before the Cat (pre Cat) and wanting to make sure.

I have read here that when the P0135 code for the heater circuit is showing like this too it usually means that the O2 sensor is toast. Is that the general consensus from most here?

I was hoping to pull my O2 sensors (pre and post Cat) and check out their conditions, wiring, connections, etc. but weather hasn't cooperated yet. I don't know if cleaning them up works out or not and just wanted to hear back from guys with more experience than I have concerning the emissions areas. Thanks, Jay W.

 

I have the same problem on my S70. I had only p0135 then I tried replacing my O2 sensor with a denso universal but now I'm getting p0130.

 

I should have submitted an update long ago on this. Since I didn't hear anything back from anyone on my original post to this thread, I went ahead and purchased an OEM O2 sensor for FCP Groton because I saw a few say the universals weren't all that good. I'm not saying they aren't OK but on to the rest of the story.

I went to swap the forwand O2 sensor out with the new one and found that the connector was just barely hanging in the socket and not making complete conctact with all four pins. I opted to not do the swap and try connecting things back up and giving it a try. I did that and reset everything. All seemed to be fine execpt that the connector just didn't feel secure.

The codes did not return but I wasn't satified with the connections. I found that the bracket that holds the sockets for both O2 sensors was more or less hanging loose. It is supposed to be mounted securely on top of the transmission housing. The forward O2 socket was broken and I have to assume that this happen when I had a transmission problem a few years back. Long story short, I was able to take it apart, all to pieces were still inside of it, and fixed it properly.