A bout a week ago I had a check engine light that I think was FF37 or 39, anyway EGR fault. The reason I say either 37 or 39 is that it somehow cleared itself today and I can't remember exactly what code displayed last week.
On the 94MY cars, at least in my experience, check engine lights NEVER just "go away", but require a reset (usually a battery disconnect) to clear.
Temperature here in the Northwest was over 100F last week so I was waiting for things to cool down before tackling the job but today, miraculously, no more check engine light.... maybe the blockage (if it was a carbon blockage) blasted itself away when I floored it and wound it up this afternoon?

Anyway, good riddance!

Larry

Hi Larry,

FF37 is an electrical circuit code, indicating a short or open circuit. I assume that means the circuit to the blue Denso solenoid.

FF39 indicates faulty system operation. I assume this is triggered if the EGR valve is supposed to be open or closed but the oxygen sensor does not sense the expected change.

I'm sure the Engine Management System manual probably explains them.

Hopefully it was a glitch and won't recur!

Cheers,

Don

Don - when PNW coastal daytime temperatures rise to 44C anything is possible!

Larry