The EGR vacuum solenoid is a simple ON/OFF type solenoid that you can easily bench test, and in this tutorial, I'll explain how to step by step.
The cool thing is that you don't need any expensive diagnostic tools to do it. No scan tool is required.
Contents of this tutorial:
- Symptoms Of A Bad EGR Vacuum Solenoid.
- How The EGR Vacuum Solenoid Works.
- Where To Buy The EGR Vacuum Solenoid And Save.
- TEST 1: Is The EGR Vacuum Solenoid Stuck Open?.
- TEST 2: Applying 12 Volts And Ground To The EGR Vacuum Solenoid.
- TEST 3: EGR Vacuum Solenoid Resistance Test.
- More 2.2L Buick Century And Oldsmobile Cutlass Ciera Test Tutorials.
You can find this tutorial in Spanish here: Cómo Probar El Solenoide De La Válvula EGR (1993-1995 2.2L Buick Century, Oldsmobile Cutlass Ciera) (at: autotecnico-online.com).
APPLIES TO: This tutorial applies to the following vehicles:
- 2.2L Buick Century: 1993, 1994, 1995.
- 2.2L Oldsmobile Cutlass Ciera: 1993, 1994, 1995.
EGR VALVE TEST: You can find the EGR valve test here:
Symptoms Of A Bad EGR Vacuum Solenoid
When an EGR system failure occurs, which includes a failure of the EGR vacuum solenoid, the fuel injection computer will set an EGR system diagnostic trouble code and illuminate the check engine light.
You'll see the following OBD I trouble code:
- Code 32: EGR system problem.
How The EGR Vacuum Solenoid Works
The EGR vacuum solenoid is the component the fuel injection computer uses to regulate the exhaust gas the EGR valve allows into the intake manifold.
In a nutshell, this is how the EGR vacuum solenoid works:
- The EGR vacuum solenoid receives 12 Volts DC as soon as the engine is started but remains OFF (does not allow vacuum to pass thru it).
- Once the engine has reached its normal operating temperature and it's under load, the fuel injection computer commands the EGR vacuum solenoid ON.
- The fuel injection computer commands the EGR vacuum solenoid ON by internally grounding it.
- In its ON state, the vacuum solenoid will allow vacuum entering its inlet port to pass to its outlet port. Since the outlet port is connected to the EGR valve, vacuum now reaches the EGR valve.
It's important to note that the EGR vacuum solenoid is normally closed. In other words, it does not allow vacuum to pass from its inlet port to its outlet port (until commanded ON).
Where To Buy The EGR Vacuum Solenoid And Save
The following links will help you comparison shop for the EGR vacuum solenoid of known automotive brands (no knock-off parts).
TEST 1: Is The EGR Vacuum Solenoid Stuck Open?
The EGR vacuum solenoid should be closed when the fuel injection computer is not commanding it ON.
In other words, the vacuum solenoid does not allow vacuum to pass from its inlet port to its outlet port.
For our first test, we'll check if the solenoid is stuck open, allowing air to pass from its inlet port to its outlet port.
NOTE: You'll need a vacuum hose to attach to the EGR vacuum solenoid's inlet port.
These are the test steps:
Disconnect the EGR vacuum solenoid from its electrical connector .
Remove the EGR vacuum solenoid from its place on the intake manifold.
Connect a vacuum hose to its inlet port .
Blow air through the vacuum hose. You can use your mouth to blow air into the vacuum hose.
Air should not pass to the outlet port .
NOTE: Air may pass thru the solenoid (its vented to atmosphere), but it should NOT come out of its outlet port.
Let's take a look at what your test results mean:
CASE 1: Air DID NOT pass through to the outlet port. This is the correct and expected test result.
The next test is to apply power and Ground directly to the EGR vacuum solenoid. For this test go to: TEST 2: Applying 12 Volts And Ground To The EGR Vacuum Solenoid.
CASE 2: Air passed through to the outlet port. This test result confirms that the EGR vacuum solenoid is bad.
Replace the EGR vacuum solenoid.