GM EVAP Vent Solenoid Testing

2002 Chevy Silverado 4.8L with a P0449 EVAP system Vent Control Circuit Low trouble code. The vent solenoid on every EVAP system is a normally open solenoid. When the computer performs a leak test, it will close this solenoid. A common problem on GM EVAP vent solenoids is they will stick open and cause EVAP large leak codes. In this particular case we are dealing strictly with an electrical system fault. The information contained in this video will apply to all ground side switched computer controlled devices (solenoids, relays, motors etc)
There were three separate codes on this truck. Here are the videos for the other two codes
How to test a fuel gauge P0463 (thermistor circuit design) - GM
   • How to test a fuel gauge (tank sendin...  
How to troubleshoot an EVAP Pressure Sensor problem P0452 - GM    • Pressure Sensor or Potentiometer Sign...  

Engine Performance Diagnostics chapter 3

Symptoms
check engine light (P0449 fault code)

Fix
replace vent solenoid (open solenoid winding)

Tests shown
how to test an EVAP vent solenoid
how to determine power or ground side switching
how to perform a circuit integrity test
how to identify circuit design on a wiring diagram
theory an operation of the computer circuitry used to control the vent solenoid
how to test the computer transistor driver
how to command the computer to turn on the vent solenoid

Tools used
scan tool (bi-directional type)
incandescent test light
digital multimeter
back-probing tools

Playlist
(Chapter 3) Transistors, Solenoids, Computer Controlled Output Testing
   • (Chapter 3) Transistors, Solenoids, C...  

Related videos
EVAP leak P0455 (vacuum cut valve-bypass valve test) - Nissan
   • EVAP  leak P0455 (vacuum cut valve-by...  
How to test an EVAP Vent solenoid (applies to all cars) - GM
   • How to test an EVAP Vent solenoid (ap...  
2008 Chevy Avalanche EVAP Vent Solenoid Test (P0449, P0455)    • 2008 Chevy Avalanche EVAP Vent Soleno...  
EVAP Leak Test P0455
   • EVAP Leak Test P0455  

For more information on this topic, I have written a “field manual” called Engine Performance Diagnostics which is available at www.scannerdanner.com as an eBook or paper book.
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Disclaimer:
Due to factors beyond the control of ScannerDanner LLC, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. ScannerDanner LLC assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. ScannerDanner LLC recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of ScannerDanner LLC, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user and not ScannerDanner LLC.