1999 Volvo V70 XTC DTC codes P1133, P1174

thepetercasey · Post by **thepetercasey** » 05 May 2014, 04:32

car starts and runs, the idle appears to 'bounce', i.e. the RPM's are erratic when cold, it bounces between 500 to 1100 RPM's. After some driving, the problem goes away. If you shut off and restart the car, the problem returns. Fuel consumption has increased. Any help would be appreciated

Post by **regent** » 05 May 2014, 10:15

Welcome to the forum,

Those two codes combined with poor performance and low fuel efficiency are indicative of HO2S going bad.
BTW, How many miles on the clock? (The oxygen sensors usually deteriorate after 100K.)

thepetercasey · Post by **thepetercasey** » 05 May 2014, 10:22

currently the vehicle has 130k miles. I just tried cleaning the MAF sensor. The problem remains, thanks

Post by **regent** » 05 May 2014, 10:38

The other part of the story is that code 1174 is an indication you are running lean (air to fuel ratio is too high), which leads to higher combustion temperatures with consequences. It is a good idea to check for vacuum leaks around the TB and intake before replacing the upstream HO2S.
Cheers!

thepetercasey · Post by **thepetercasey** » 05 May 2014, 11:15

thanks & Cheers