Error code 332 and 558 - bad EGR / EVR

[blue_lightning]

I was getting a code of 332 (EGR valve not opening) so I replaced the EGR and the EVR. Now I'm getting a code of 558 (Electrical circuit of (EVR) electronic vacuum regulator). I removed the new EVR and reinstalled my old one and got the same code so I put the new one back on. I can't blow air through vacuum ports, which, according to various web pages, implies the EVR is OK.

Are there other simple tests I can do?

 

[bluesman2333]

The DPFE is the usual culprit in EGR problems. It can be working partly and still seem to be OK but it isn't.

 

[MrShorty]

My experience with those 500 solenoid codes (I'm assuming KOEO here, since my code list indicates a 558 can only be a KOEO code) is that there are 2 basic causes: a full open in the circuit or a short to ground. The circuit is a pretty basic DC circuit, so it shouldn't be too difficult to track down with a multimeter and a wiring diagram.

I haven't tinkered with a '94, but I remember using the output state test and a vacuum pump to test the EVR solenoid on my BII. When the valve is closed, the vacuum leaks off a lot slower than when the valve is opened. The stickies in the EEC-IV forum describe how to get into output state test mode.