Ocasional 315 and 436 codes simultaneously

icelandic · Post by **icelandic** » 14 Dec 2009, 03:35

Every 200 miles or so I am getting the 315 and 436 codes. They always pop up simultaneously. One is EVAP fault the other is rear O2 compensation. Has anyone run into this? What is going on? Engine runs smoothly and no noticeable performance impairment.

Icelandic

Macs&Volvos · Post by **Macs&Volvos** » 14 Dec 2009, 06:40

Any change in gas mileage?

It could be a leak in the exhaust allowing air into the system, or some kind of vacuum leak.

How old is the O2 Sensor?

FCPEURO · Post by **FCPEURO** » 14 Dec 2009, 06:43

+1

If your rear O2 is old, I would change it just because.

Post by **jblackburn** » 14 Dec 2009, 07:15

Check the plastic elbow at the rear wheel well leading into the charcoal canister. They like to crack and cause the car to throw those codes.

icelandic · Post by **icelandic** » 15 Dec 2009, 04:22

Both O2 sensors are 60K old. Apparently no change in mileage. Next weekend I will take out the battery tray and will check the plastic pipes from the canister as well as the rubber elbow.