99 V70XC P0134 Code with Sputters

JeffHicks · Post by **JeffHicks** » 08 Sep 2014, 18:21

Hey Guys - the other day my buddy brought over his 99XC. Problem was that the exhaust pipe broke right at the back of the cat converter. Because neither of us know a guy with a welder, and he doesn't want to "go the whole route" with all new exhaust, we "fixed" it by inserting a 2-1/8th "tube" inside the pipe, and sliding the pieces back together.

About half hour later, his CEL light came on, and he was throwing the P0134 code - for a bad O2 Sensor. He said it also would run sluggish when he really laid into the accelerator.

Is it possible that that little "tube" created enough back pressure to throw that code? Did we jimmy the sensor somehow? Is it possible that this is just completely random and coincidental?

Post by **Ozark Lee** » 08 Sep 2014, 19:57

How far into the catalytic converter did the pipe go? On a '99 XC the rear oxygen sensor is actually screwed into the catalytic converter and I suppose if the pipe went in far enough it could have blocked the flow around the sensor. I'm not sure how things flow through that style of converter since I've, thankfully, never had to replace one and had a chance to look at it close up out of the car.

That still shouldn't change the performance just due to the sensor error. All the rear sensor does is monitor the efficiency of the converter - a tattletale of sorts.

...Lee

JeffHicks · Post by **JeffHicks** » 08 Sep 2014, 21:34

Ozark Lee wrote:How far into the catalytic converter did the pipe go? On a '99 XC the rear oxygen sensor is actually screwed into the catalytic converter and I suppose if the pipe went in far enough it could have blocked the flow around the sensor. I'm not sure how things flow through that style of converter since I've, thankfully, never had to replace one and had a chance to look at it close up out of the car.

That still shouldn't change the performance just due to the sensor error. All the rear sensor does is monitor the efficiency of the converter - a tattletale of sorts.

...Lee

Thanks for the reply!

The pipe is only pushed (maybe) half-inch into the cat converter. I don't think there's any way the pipe itself could have hit the sensor.

This car is a turbo model, which makes me wonder about the remote possibility that that tiny little bit of "interference" in the exhaust system could set off the code.

I know these cars are apt to need the upstream sensor replaced, but the timing of this just seems very very odd.