O2 sensor bank 1 sensor 1

[Hadies]

Hi guys,
I have an intermittent issue with an O2 sensor (bank 1 sensor 1). Had the EML flash up a couple of times with the error codes P2251 and P0130. Car seems to be running OK. Idles fine, no misfires or flat spots.
Both times the EML flashed up cruising/pulling away at around 20mph.

I took the car to my local garage and they claimed it's an engine drop job to gain access to the affected sensor.

Anyone have experiences they can share?
Thanks,
Hadrian

[IanH755]

Sensor 1 is the 1st lambda right at the top of the downpipe in the elbow just behind the pre-cat. An RS6 specialist can remove the downpipe without dropping the engine by lowering the subframe for access but there's a slight risk that one of the studs on the back of the turbo can shear (has happened to people on here) which then means the engine will have to be dropped anyway to fix the turbo stud.

If everything goes OK it's far cheaper to accept the slight risk and do this (£800-ish from memory and 1 days work) than to drop the engine (£2500+ and 3 days work) however. despite the costs, there are other advantages to dropping the engine as it gives you access to fix the common coolant pipes, oil pump seals, general leaks/seals on the engine etc.

In the end it's down to cost but just remember that, even if you decide to choose the cheaper option, there's a small risk that it might end up being an engine out job in the end anyway (turbo studs).

[don0301]

Turbo studs aren't necessarily engine out.

I had 3 break when I had my downpipes done, all repaired in situ, was a real PITA tho he said.

[IanH755]

True TBF, there's only 1 stud which requires the engine dropped.

[Hadies]

Cheers for the input gents. The specialists around me have all suggested an engine drop. I wouldn't be as annoyed if the oil seal and coolant pipes hadn't already been done.
I must've missed this one off the hilarious-things-to-go-wrong-with-the-car list.
Any technical people make sense of the data in the photos?