TEST 2: Testing The Resistance Of The Solenoids
Now that you've confirmed the EGR valve is getting 12 Volts, we'll check the internal resistance of solenoids A, B, and C (of the EGR valve).
This resistance test will determine if the solenoids have suffered an internal short-circuit or an open-circuit problem.
Probing the EGR valve male terminals (with the multimeter test leads) can be a challenge since they're recessed in the middle of the EGR valve.
It'll be easier to test the solenoids' resistance if you remove the EGR valve from its place on the intake manifold.
If the solenoids haven't suffered an internal short-circuit or open-circuit problem, we'll move on to the next test.
NOTE: This test is performed on the male spade terminals of the EGR valve itself.
IMPORTANT: The EGR valve must be at ambient temperature before removing and testing it. If the engine has been running for any length of time, the EGR valve will be hot! Let the engine cool down completely before removing and testing the EGR valve.
OK, these are the test steps:
- 1
Remove the EGR valve from the intake manifold.
- 2
Set your multimeter to Ohms mode.
- 3
Connect the red multimeter test lead to male terminal D.
- 4
Probe terminal A with the black multimeter test lead. Terminal A belongs to solenoid A.
- 5
You should see a resistance value around 12 Ohms.
If the solenoid has a short-circuit problem, you'll see a value around 0 Ohms on your multimeter.
If the solenoid has an open-circuit problem, you'll see a value in the thousands of Ohms (K Ohms) or the letters OL (digital multimeter). - 6
Repeat steps 4 to 5 on terminals B and C.
Let's see what your test results mean:
CASE 1: The resistance of each solenoid is within the indicated value. This is the correct and expected test result.
The next step is to apply power and Ground to each solenoid. Go to: TEST 3: EGR Solenoid A Performance Test.
CASE 2: The multimeter reported a short-circuit problem in one of the solenoids. This test result tells you that the solenoid is bad. Replace the EGR valve.
CASE 3: The multimeter reported an open-circuit problem in one of the solenoids. This test result tells you that the solenoid is bad. Replace the EGR valve.
TEST 3: EGR Solenoid A Performance Test
As mentioned earlier, the EGR valve has three solenoids. The fuel injection computer controls when each solenoid opens or closes by grounding or un-grounding them.
As the computer commands each solenoid open, the solenoid opens a port that allows exhaust gas to pass thru the EGR valve.
In photo 2 of 3 above, I've labeled the EGR valve ports (that open/close) with the letters A, B, and C.
You and I can bypass the computer and apply power and Ground to the appropriate male spade terminals of the EGR valve and actuate each solenoid and see the port it controls open.
This test section will focus on performance-testing EGR valve solenoid A with a 9 Volt alkaline battery.
Specifically, we'll use a 9 Volt battery to apply power and Ground to the EGR valve's male terminals D and A, respectively.
If solenoid A functions correctly, powering it up should cause it to open the port labeled with the letter A (see photo 2 of 3).
NOTE: We won't use the vehicle battery (for power or Ground) to actuate any of the EGR valve solenoids for test safety reasons. The 9 Volt alkaline battery I'm referring to is the one that's used in smoke detectors and other small portable appliances (see photo 3 of 3 in the image viewer above).
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, these are the test steps:
- 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
Connect the other end of the red jumper wire to terminal D (see the illustration above).
- 3
Connect one end of the black jumper wire to terminal A.
- 4
Connect the other end of the black jumper wire to the negative (-) terminal of the 9 Volt battery.
- 5
You should hear an audible click and the port labeled with the letter A should open.
- 6
Disconnect the 9 Volt battery from the black jumper wire.
- 7
The EGR valve port A should close.
- 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 A. This is the correct test result and confirms solenoid A is functioning correctly.
Your next step is to test solenoid B. Go to: TEST 4: EGR Solenoid B Performance Test.
CASE 2: The solenoid DID NOT 'click' and DID NOT open port A. This test result confirms that solenoid A is bad. Replace the EGR valve.
CASE 3: The solenoid 'clicked' but DID NOT open port A. This test result confirms that solenoid A is bad. Replace the EGR valve.
