How To Test The EGR Valve (1990-1993 3.1L V6 Buick Regal, Oldsmobile Cutlass Supreme)

TEST 4: EGR Solenoid B Performance Test

This test section will focus on the performance test of EGR valve solenoid B.

We'll apply power and Ground from the 9 Volt alkaline battery to the EGR valve's male terminals D and B, respectively.

Once solenoid B is powered, the port labeled with the letter B (on the underside of the EGR valve) should open.

IMPORTANT: To accomplish this test without complications or a 'false-positive' test result, you'll need jumper wires with insulated alligator clips. You can buy these at your local auto parts store or purchase them online here: Jumper Wires With Insulated Alligator Clips (at: amazon.com).

Alright, let's get testing:

1. 1

   Connect one end of the red jumper wire to the positive (+) terminal of the 9 Volt battery.
   
   NOTE: This test is done with the EGR removed from the engine.

2. 2

   Connect the other end of the red jumper wire to terminal D (see the illustration above).

3. 3

   Connect one end of the black jumper wire to terminal B.

4. 4

   Connect the other end of the black jumper wire to the negative (-) terminal of the 9 Volt battery.

5. 5

   You should hear an audible click and the port labeled with the letter B should open.

6. 6

   Disconnect the 9 Volt battery from the black jumper wire.

7. 7

   The EGR valve port B should close.

8. 8

   Repeat steps 4 thru 7 several times to make sure of your test results.

Let's take a look at what your test result means:

CASE 1: The solenoid 'clicked' and opened port B. This is the correct test result and confirms solenoid B is functioning correctly.

Your next step is to test solenoid B. Go to: TEST 5: EGR Solenoid C Performance Test.

CASE 2: The solenoid DID NOT 'click' and DID NOT open port B. This test result confirms that solenoid B is bad. Replace the EGR valve.

CASE 3: The solenoid 'clicked' but DID NOT open port B. This test result confirms that solenoid B is bad. Replace the EGR valve.

TEST 5: EGR Solenoid C Performance Test

In this last test section, we'll performance-test EGR valve solenoid C.

We'll apply power and Ground to the EGR valve's male terminals D and C, respectively.

Once solenoid C is powered, the port labeled with the letter C (on the underside of the EGR valve) should open.

IMPORTANT: To accomplish this test without complications or a 'false-positive' test result, you'll need jumper wires with insulated alligator clips. You can buy these at your local auto parts store or purchase them online here: Jumper Wires With Insulated Alligator Clips (at: amazon.com).

Alright, let's get testing:

1. 1

   Connect one end of the red jumper wire to the positive (+) terminal of the 9 Volt battery.
   
   NOTE: This test is done with the EGR removed from the engine.

2. 2

   Connect the other end of the red jumper wire to terminal D (see the illustration above).

3. 3

   Connect one end of the black jumper wire to terminal C.

4. 4

   Connect the other end of the black jumper wire to the negative (-) terminal of the 9 Volt battery.

5. 5

   You should hear an audible click and the port labeled with the letter C should open.

6. 6

   Disconnect the 9 Volt battery from the black jumper wire.

7. 7

   The EGR valve port C should close.

8. 8

   Repeat steps 4 thru 7 several times to make sure of your test results.

Let's take a look at what your test result means:

CASE 1: The solenoid 'clicked' and opened port C. This is the correct test result and confirms solenoid C is functioning correctly.

If all three solenoids tested OK (and all three ports opened/closed), you can conclude the EGR valve itself is functioning correctly and isn't behind the EGR diagnostic trouble code.

The most likely cause of the EGR valve trouble code (illuminating the check engine light) is one of the following:

• Carbon buildup blocking the EGR port in the intake manifold.
• Carbon buildup blocking the EGR passage in the EGR adapter to exhaust manifold pipe.

CASE 2: The solenoid DID NOT 'click' and DID NOT open port C. This test result confirms that solenoid C is bad. Replace the EGR valve.

CASE 3: The solenoid 'clicked' but DID NOT open port C. This test result confirms that solenoid C is bad. Replace the EGR valve.

More 3.1L Buick Regal And Oldsmobile Cutlass Supreme Test Tutorials

If this tutorial was helpful, be sure and take a look at all of the 3.1L Buick Regal and Oldsmobile Cutlass Supreme diagnostic tutorials in this index:

• GM 3.1L Index Of Articles.

Here's a sample of the tutorials you'll find there:

• How To Test The Fuel Pump (1989-1993 3.1L V6 Buick Regal, Oldsmobile Cutlass Supreme).
• How To Test The TPS (1989-1993 3.1L V6 Buick Regal, Oldsmobile Cutlass Supreme).
• How To Test The Alternator (1989-1993 3.1L V6 Buick Regal, Oldsmobile Cutlass Supreme).
• How To Test A Blown Head Gasket (3.1L V6 Buick, Oldsmobile).