Need help with O2 sensor on a Neon - Moparchat

Dan S · #1 03-08-2000, 05:20 AM

I am getting code 21 from the CEL. It is one of the O2 sensors. How do I figure out if it is upstream or downstream sensor?

Thanks
Dan S

Dean Stillie · #2 03-09-2000, 01:37 AM

Your best to get it read with a scanner any other way around this may just cause you more money and /or grief

supergoob · #3 03-13-2000, 06:37 AM

Most of the time its the down stream o2 sensor. Due to the preheater shorts out in it.Like Dean said this would be the more probable way or you have a 50-50 chance on picking the correct one.

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