How to test Intake Valve Control Solenoids (codes P0028, P0082) - Subaru

On this system the intake valve lift is varied by two different cam lobes. A low lift lobe and a high lift lobe. I misspoke in the video calling this a variable valve timing or VTEC mechanism. This system does not vary cam timing, but it does vary intake valve lift. What was unusual with this fault was when you have "circuit low" type codes, this is almost always an electrical problem to the solenoid or the solenoid itself is open. However everything tested fine electrically and we found that this engine was very low on oil. Once we added oil, these codes did not return. Engine Performance Diagnostics chapters 2 and 3 Symptoms - check engine light (P0028, P0082 codes) - poor performance Fix - added 2-3 quarts of oil to the crankcase Tests shown - how to identify oil switching solenoid valve circuit design - how to identify variable valve lift pressure switch circuit design - how to test both the solenoid and pressure switch - why manufacturer flow charts suck Tools used - incandescent test light - scan tool - lab scope - digital multimeter Playlist - (Chapter 3) Transistors, Solenoids, Computer Controlled Output Testing https://www.youtube.com/playlist?list=PLE9BA8CBD51B8C48E Related videos - Honda VTEC System Testing (P1259 trouble code) https://youtu.be/vTis29MQC4U - How to test a computer controlled solenoid (power/ground side identification) https://youtu.be/kQz3g4HIWgs - Intake/Exhaust Camshaft Actuator Solenoid test (P0010, P0011) - GM 2.4 https://youtu.be/_RF4yct8J54 - How to test cam/crank actuator solenoids (P0010, P0013) 2008 GM 2.4 L https://youtu.be/6B7HrBN2tvY 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. Want even more diagnostic training? Whether you are a DIY trying to fix your own car, someone looking to become an auto technician, or a current auto technician that wants to get more into diagnostics, subscribe to ScannerDanner Premium https://www.scannerdanner.com/join-scannerdanner-premium.html There is a 14 day free trial. On ScannerDanner Premium I will bring you right into my classroom at Rosedale Technical College. You will find page for page lectures taken right from my book as well as exclusive classroom type case studies. What is so special about these classroom case studies? I pull live problem vehicles directly into my classroom and we troubleshoot them in real time, using and applying the theory and testing procedures we learn during the classroom lectures. There is no better on-line training of how to troubleshoot automotive electrical and electronics systems anywhere! 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.