Over the past 6 months my check engine light comes on and goes off randomly. I have always thought it was the gas cap and recently had the codes pulled from the computer at the dealer. They said the left rear oxygen sensor was going bad. They quoted me 2.2 hours labor to install plus $335 for the part. These seems a bit excessive to me. Anyone done this one? I am out of warranty. I did find the part for $164.

Thanks for any advice,
Roger

i did the left rear O2 on my 545 in less than 20 minutes in my garage. if you have any mechanical skills at all it is an easy job, although i would suggest an O2 sensor socket, which I got for ~30 at the time I bought the sensor.

do i just need to drive the front wheels up on ramps to access?

yes, and you will have to remove the plastic underbody panels. it's just a few screws around the perimeter then they fall off. I took off the front ones to get access to the rearmost one and just left that one hanging while I did the swap. no way is it worth paying the dealer for this job.

check advance auto and rmeuropean for pricing on the sensor. I don't know if it's the exact same part # as mine, so I don't know if the $164 is reasonable.

ok thanks for your help. You know these cars have 4 of these oxygen sensors at about 150 each. Crazy!!!

Make sure the car is cooled down as the o2 sensors are located next to the catalytic converter ..and if I remember correctly, BMW recommended replacing all o2 sensors at 100k miles

how many people actually do that?

None....its BMW recommended maintenance

O2 Sensors should be covered under the emissions warranty. Your dealer should know that and if I'm not mistaken that warranty is 8 years and 80K miles!

http://www.epa.gov/oms/consumer/warr95fs.txt

only the main computer and catylist is covered that long.