Car throws a code 32 a high speeds only (EGR Solenoid). I understand the computer uses a number of inputs to send 0 volts or 12 volts to the ECM solenoid. So how does the computer get feedback to set an error code?

 

The ecm energizes the solenoid and if the vehicle is at steady cruise and its going at above 50 mph, the computer looks for a drop in manifold pressure. If it doesnt see the pressure change that its looking for, a code 32 will set. The ecm has no way of knowing if the egr is even physically hooked up, it just looks for the effects of the egr opening.

 

So the next logical question is what sensor does the computer get a manifold pressure reading from? Thanks

 

Also on some cars there is a temp sensor screwed into the side of the EGR valve. The ecm can look for a temp change there to see if the valve is working....

 

If the car is your rs, then the 8746 just has teh solenoid hooked up to a standard style vacuum operated egr. The ecm gets the manifold pressure from the map sensor. Odds are, your egr problem is due to either exaust mods or a faulty/clogged valve.