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Old 12-12-2012, 12:00 AM   #40
Registered User
Join Date: Jul 2007
Location: Show-me state
Posts: 695
My Ride: 2001 BMW 330I
Nice job to plot them out.
Now you can clearly see that O2-21 is good, but O2-11 is bad.
You need to replace the O2-11 (Bank 1, pre-cat sensor) for sure.
One odd thing is that post cat sensors are starting at 0 volt instead of starting around 0.4 volt. And they took almost 3 minutes to go alive. My bet is that rear sensors are going bad too.
Amazon seems be the best source (cheapest) for Bosch OEM-fit O2 sensors.

I will do following steps.
1. Replace O2-11 and see if it is the silver bullet
2. If that didn't fix, disconnect one of post-cat O2 connector and see if that sets codes for O2.
3. If codes are set with a disconnected post-cat O2 sensor, replace both post-cat O2 sensors.

For Evap test, drive with the gas cap removed and see if it sets the evap code.
If no code is set, then either evap test criteria are not met or your DME needs reprogramming.

Last edited by dslboomer; 12-12-2012 at 12:02 AM.
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