TEST 4: Making Sure The EGR Valve Pintle Position Sensor Is Receiving Ground
Up to this point, you've confirmed the following:
- The pintle position voltage signal is stuck in one voltage value (TEST 2).
- The pintle position sensor is receiving 5 Volts DC (TEST 3).
Now we'll focus on making sure the pintle position sensor is receiving Ground with the key ON but engine off (KOEO).
The terminal that delivers Ground to the pintle position sensor is the one labeled with the letter B in the illustration above.
CAUTION: Ground is provided internally by the PCM. So be careful and don't short this terminal (circuit) to battery 12 Volts, or you'll fry the PCM. The multimeter voltage test suggested in the instructions below is a safe way to check for the presence of Ground in this circuit.
These are the test steps:
- 1
Place your multimeter in Volts DC mode.
- 2
Disconnect the EGR valve from its pigtail connector.
- 3
Connect the red multimeter test lead to the battery positive (+) terminal.
- 4
Gently probe the female terminal labeled with the letter B with black multimeter test lead.
- 5
Turn the key to the RUN position but don't crank or start the engine.
- 6
The multimeter should read 10 to 12 Volts DC.
Let's interpret your test results:
CASE 1: The multimeter registered 10 to 12 Volts. This is the correct and expected test result and confirms the EGR valve pintle position sensor is receiving Ground.
You can conclude that the EGR valve is bad and needs replacement if you have:
- Confirmed the EGR valve pintle position signal is stuck in one value as you opened/closed the pintle (TEST 2).
- Confirmed the EGR valve pintle position sensor is receiving 5 Volts (TEST 3).
- Confirmed the EGR valve pintle position sensor is receiving Ground (this test section).
CASE 2: The multimeter DID NOT register 10 to 12 Volts. This test result confirms the EGR valve pintle position sensor is not receiving Ground. Without it, the EGR valve's pintle position sensor will not be able to create its position signal.
Although it's beyond the scope of this tutorial, your next step is to find out why Ground missing and restore it.
TEST 5: Making Sure The EGR Solenoid Is Getting 12 Volts
Besides a pintle position sensor, the EGR valve comes equipped with a solenoid.
When the fuel injection computer energizes the solenoid, the pintle opens and allows exhaust gas into the intake manifold.
The terminal that supplies 12 Volts to the solenoid is the one labeled with the letter E (see illustration above).
Depending on the specific year of your 4.3L Chevy S10 pickup or GMC Sonoma, the EGR valve solenoid receives 12 Volts from a fuse or from the PCM. Here are the specifics:
- 1996-1997 -The EGR valve solenoid gets 12 Volts from a fuse.
- 1998-2001 -The EGR valve solenoid gets 12 Volts from the fuel injection computer.
These are the test steps:
- 1
Place your multimeter in Volts DC mode.
- 2
Disconnect the EGR valve from its pigtail connector.
- 3
Connect the black multimeter test lead to the battery negative (-) terminal.
- 4
Gently probe the female terminal labeled with the letter E with the red multimeter test lead.
- 5
Turn the key to the ON position but don't crank or start the engine.
- 6
The multimeter should read 10 to 12 Volts DC.
Let's interpret your test results:
CASE 1: The multimeter registered 10 to 12 Volts. This is the correct and expected test result and confirms the EGR valve solenoid is receiving power.
Your next step is checking the solenoid's resistance. Go to: TEST 6: EGR Solenoid Resistance Test.
CASE 2: The multimeter DID NOT register 10 to 12 Volts. This test result confirms the EGR valve solenoid is not receiving Power. Without it, the EGR valve solenoid can not move the pintle (up/down).
The most likely cause of these missing 12 Volts is an open-circuit problem in the wire that connects to terminal E. Although it's beyond the scope of this tutorial, your next step is to find out why these 12 Volts are missing and restore them.
