FYI,

I had the same problem a long time ago, right after I got my car used.
The light came on right after the money exchange hands and just before a smog test.

The PO had spent big bucks with an INDY trying to fix it according to some repair records she left me. Evidently, the plan or trick of her associate, was to keep pulling off a little red wire, from the fender terminal, to reset the light after each of the test drives.

I found it to be a valve on the fender to be the culprit. It turns on the EGR, via vacuum, to operate it. The computer compares two-heat probes sensors in the EGR ports for temperature change to confirm operation.

The valve has a bleed port under the cap that is on top. It has a piece of foam rubber in there to act as an air filter. It becomes rotten and plugs the hole beneath it. I replaced it with polyester fill fiber. This replacement synthetic material will keep dust out and will not rot again.

It has been over five years now. It was a cheap fix. I have been very happy with the car. That INDY, he lost a steady boat payment.


Just exercise the valve with power with 12 volts and see if you can get some air/vacuum to pass through it. Note which way the hoses come off. I think it can make a difference to the internals of the valve. I think there may even be yellow dot on one of the ports to match a hose, one way or the other.

It has been awhile, so do not hold me to it!

I hope this is it. Because having to dink with any exhaust gas fittings, might be a bear.

Phil