Question on Boxster 02 Sensor

Hi, I've recently had my 2004 tip in a garage where they've replaced the gearbox. When they returned the car it has a cel on and they explained that they've had a quick look but can't see the problem but might need 2 new o2 sensors. I've rigged it up to my scanner and get P0134 and P0154 codes. If I reset the codes they return within 2 or 3 miles. I've read it's rare for both sensors to fail at the same time - would you suggest checking anything else before I get them both replaced? Car seems to be running fine. 2004 2.7 986

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This post was auto-generated based upon a question asked on our tech article page here: Porsche Boxster Oxygen Sensor Replacement - 986 / 987 (1997-08) - Pelican Parts Technical Article

[Nick at Pelican Parts]

The sensors may have been left unplugged or damaged during the repair. I check them for physical damage.

- Nick

[Jay Laifman]

I am getting P0154. So this is the one on the driver's side. Before buying a new sensor, does it make sense to swap the left and right ones to see if the code changes? If it is the sensor, would it then be P0134?

[mikefocke]

is not like an aging sensor.

Wiring issue? What happened when the trans was worked on?

More here.

[Jay Laifman]

Thanks Mike.

I read your long web page. Very nice!

Unfortunately, unless I missed it, it doesn't seem to address 0154.

The 0154 has been somewhat intermittent. I would reset the codes and it wouldn't come back for months. Sometimes the CEL would come on, but then turn itself off after a day or two.

I will say that last week, for the first time, instead of 0154, I got 1128 and 1130. I've since cleaned the MAF and throttle, and checked the oil vacuum. They haven't come back since. But interestingly, 0154 came up almost immediately and seems to be lasting. That's why I posted this question.

I'm still not sure I understand your response. If the problem is wiring in the sensor or the sensor connection, if I swapped the sensors L and R, wouldn't that be a good way of eliminating that as a problem? I've seen way too many guys with 0154 just jump and buy a new sensor, only to have the issue come back up. I'm trying to avoid that first mistake.

[Jay Laifman]

As to the transmission, I pulled the transmission a few years ago to replace the IMS bearing and the clutch. That went relatively smoothly. I can't remember for sure if the 0154 started before or after that. I'm assuming you are suggesting that the wires to the sensor got stretched when the engine moved during that work. Possibly. But that brings me back to my swap the sensors test idea.

[mikefocke]

Heat caused failure?
Of the sensor or the wiring?
Is the sensor original?
Was the sensor soldered to the wiring?
Has the plug been reseated?

Yes swapping could be helpful if it is the sensor but around 60k it isn't unexpected to replace the two between the engine and the cats. The after-cats ones seem to last longer.

[Jay Laifman]

No excessive heat that I'm aware of. So Cal.
Yes, original sensor.
No solder.
Not touched since factory.

But, over 100k miles. Very well maintained and cared for (admittedly by a long time 1973 Porsche 911 owner, who has succumbed to the Porsche excessive care disease!). But still, over 100k.