TEST 2: Making Sure The EVAP Solenoid Is Blocking Fuel Vapor Intake
When the fuel injection computer doesn't give the EVAP purge solenoid the ON signal, it stays closed in its OFF state.
In this OFF state, it stops any fuel vapor from passing thru it from the carbon canister into the intake manifold.
For this test part, we're gonna take it off the intake manifold and blow air thru it to make sure it's really in its closed state.
These are the test steps:
- 1
Disconnect the plastic line that connects the EVAP purge solenoid's fuel vapor inlet port.
This plastic line is the one that connects the EVAP purge solenoid to the carbon canister. - 2
Disconnect the EVAP purge solenoid from its connector.
- 3
Remove the EVAP purge solenoid from its place.
This is done by removing the bolt from the solenoid's mounting bracket. - 4
Blow air into the purge solenoid's fuel vapor inlet port (see photo above).
I usually use a clean piece of rubber fuel/vacuum hose over the inlet port and my mouth for this step. - 5
Air should NOT pass thru' the EVAP purge solenoid.
Let's take a look at what your test results mean:
CASE 1: Air DID NOT pass thru' the EVAP purge solenoid. This is the correct and expected test result.
The next step is to bench-test the EVAP purge solenoid and see if it 'opens'. For this test go to: TEST 3: Bench Testing The EVAP Purge Solenoid.
CASE 2: Air passed thru' the EVAP purge solenoid. This result tells you that the EVAP purge solenoid is bad and is stuck in its 'open' state.
Replace the EVAP purge solenoid to solve the P0443 trouble code lighting up the check engine light.
TEST 3: Bench Testing The EVAP Purge Solenoid
For our third and final test, we're gonna check if the EVAP purge solenoid actually opens up and allows air to pass through when we apply 12 Volts and Ground from the your van's battery.
To do this test safely, it's super important to use jumper wires with insulated alligator clips. If you don't, there's a risk of frying the solenoid if the wires accidentally touch each other and create a short circuit.
Once we power up the EVAP purge solenoid, it should open up and let air flow through. If it doesn't, then it's a clear sign that it's bad and needs to be swapped out for a new one.
OK, let's get going:
- 1
Connect the red insulated jumper wire to the male terminal labeled with the letter A in the photo above.
- 2
Connect the other end of the red insulated jumper wire to the battery positive (+) terminal.
- 3
Connect the insulated black jumper wire to the male terminal labeled with the letter B.
- 4
Connect the other end of the black insulated jumper wire to the battery negative (-) terminal.
- 5
The EVAP purge solenoid should make a 'click' sound as soon as you apply Ground to it.
With 12 Volts and Ground applied to the EVAP purge solenoid, the solenoid should be 'open' and should allow air to pass thru' it. - 6
Blow air into the vapor inlet port of the solenoid (you can use your mouth) to make sure that the solenoid has opened and is allowing air to pass thru' it.
Let's take a look at what your test results mean:
CASE 1: The EVAP purge solenoid activated and allowed air to pass thru' it. This is the correct and expected test result.
You can conclude that the EVAP purge solenoid is good if you have:
- Confirmed that the EVAP solenoid is getting 10 to 12 Volts (TEST 1).
- Confirmed that you CAN NOT blow air thru' the EVAP purge solenoid in its OFF state (TEST 2).
- Confirmed in this test section that the EVAP purge solenoid opens and allows air to pass thru' it (when you applied 12 Volts and Ground to it).
CASE 2: The EVAP purge solenoid activated but DID NOT allow air to pass thru' it. This test result lets you know that the EVAP purge solenoid is bad and needs to be replaced.
CASE 3: The EVAP purge solenoid DID NOT activate and DID NOT air to pass thru' it. This test result lets you know that the EVAP purge solenoid is bad and needs to be replaced.
More Chevy Express/GMC Savana Articles And Tutorials
You can find a complete list of articles and diagnostic tutorials for the V8 Chevy Express and GMC Savana here:
Here's a sample of the tutorials you'll find in the index:
- How To Test For The Fuel Pump (2008-2013 V8 Chevy Express, GMC Savana).
- How To Test For A Blown Head Gasket (2003-2013 V8 Chevy Express, GMC Savana).
- How To Diagnose An Engine Cranks But Does Not Start Problem (2003-2007 V8 Chevy Express, GMC Savana).
- How Can I Tell If The Automatic Transmission Is Bad? (2003-2013 Chevrolet Express, GMC Savana).
If this info saved the day, buy me a beer!
