EGR Solenoid

General Information

1985-88 VALVE, EGR electric vacuum regulator solenoid
               10038324 $98.82 (price on 12-14-94)

Its function is to pulse on the EGR by applying vacuum at a pulsed rate, determined by the ECM, to the EGR. Incorporated with this valve is a vacuum switch that sents a "yes" back to the ECM that the EGR valve is indeed getting vacuum when the ECM dictates EGR. Notice I use the word valve for this controller and avoid calling the EGR a valve. Well, the EGR is also a valve, but so as not to confuss, I'll refer to the EGR valve simply as the EGR. What we have here is a valve controlling another valve.

There are three lines to the valve:

a) vent (goes back to the air cleaner)
b) manifold vac
c) on demand vac. to the EGR. This is the line that the valve controls.

Basically it self tests. If the valve doesn't work, then the ECM sets a code 32. If it leaks, there would be vacuum at the EGR all the time. Check for vac. at the EGR at idle and there should be none.

From: Tin Man


   (to EGR valve)            (from engine)
_____vacuum line_____     ____vacuum line______
     |               |   |
     |               |   |
     |          -----|---|----
     |          |     EGR    |
     |          |  SOLENOID  |______
     |          |            |____  |
     |          |____________|   _|_|________
     |                           || |-------|A------PNK
_____|_____                      ||         |
|         |_____________         ||---------|B---GRY/RED
|         |_________    |        |          |
|_________|         |   |--------|----------|C--- DK GRN
EGR diagnostic      |            |          |
switch              |------------|----------|D--- BLK/WHT
                                 Control circuit

The switch is three parts, an EGR solenoid, EGR vacuum diagnostic switch and control circuit.

The pink wire (A) is 12 volts from IGN fuse. The ECM grounds gray/red (B) wire which opens the EGR solenoid and lets vacuum go to the EGR valve and diagnostic switch. When vacuum is applied to the EGR valve, it is also applied to the diagnostic switch which closes the switch (Dark green (C) and black/white (D) wires) If the diagnostic switch does not close the ECM "knows" no vacuum is being sent to the EGR.

To test the EGR solenoid, it is normally closed, no vacuum should go through until (B) is grounded with 12 volts on (A). Ignition on will send 12 volts to (A). Grounding diagnostic terminal (same as reading codes) will ground (B).

To test EGR diagnostic switch, it should be normally open. Applying vacuum to switch should close it (C and D).

There is also a filter on the end of the EGR solenoid, on the end with the vacuum hose that runs to the air cleaner.

From: Scott Backer

Removal and Installation

Removal - V6 models only

One bolt (10mm) holds it on. You will have to unclip the electrical connector, pull the one flexible hose off of the front end, and pull the two tubes (which are connected together, and are different sizes so they will only fit on the correct way) off the other end.

From: Sketch


"Does anyone know if GM sells the EGR solenoid filter separately and if so what is its aprroximate price and part number? Does any aftermarket company sell it?"

Yes, GM has the filter available separately, I'll see if I can find it again, however, you don't always need to replace the filter. It can be back flushed with compressed air to clean it out. I've done this, and it works great.

From: Bob

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