Contour Enthusiasts Group Archives Forums General Troubleshooting MIL Eliminators and CEL

I installed a set of MSDS headers on my 98 Mystique earlier this year and I've been plagued by an occasional CEL since then. I installed the MIL eliminators that came with the headers but my scan tool reports that I have a defective Bank 1, downstream O2 sensor. The CEL stays on a few days and then goes off for a few. I've checked the connections and things seem to be okay there.

My question is, does any current even go through that O2 sensor with the MIL eliminators in place? I'd hate to spend $69 on a new sensor if it's not going to solve the problem.

Jeff

Well, you can't use a real O2 sensor there with headers, or that CEL will always be on. The MILs are used to send false signals to the PCM to make it think that the downstream sensors are switching like they should.

So, to answer your question, yes - current does flow through the MIL Eliminators. It's either a bum connection (as you've already checked) or the MIL is bad.