Welcome to the North American Subaru Impreza Owners Club Thursday October 22, 2020
Home Forums Images WikiNASIOC Products Store Modifications Upgrade Garage
Go Back   NASIOC > NASIOC Technical > Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo)

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.

* As an Amazon Associate I earn from qualifying purchases. 
* Registered users of the site do not see these ads. 
Thread Tools Display Modes
Prev Previous Post   Next Post Next
Old 11-04-2019, 06:18 PM   #1
Scooby Newbie
Member#: 485056
Join Date: Apr 2018
Default Trick EVAP System Leak Detection - 2004 WRX

Hello all,

I have a 2004 WRX and I am looking to delete my EVAP system, however there is one thing holding me back at the moment. Accordingly, the ECM runs a check that does the following:

Mode A (Evaluation of EVAP. generation amount)
Calculate the tank pressure change amount (P1).

Mode B (Negative pressure seal)
Introduce the intake manifold pressure into the fuel tank, and reduce the tank pressure to the target pressure.

Mode C (Pressure increase check/premature OK judgment)
Wait until the tank pressure returns to the target value. If the tank pressure does not return, perform the premature OK judgment.

Mode D (Negative pressure change amount measurement/EVAP. leakage diagnosis)
Calculate the tank pressure change value (P2), measure the diagnosis value using P1 calculated in Mode A. Perform the EVAP. leakage diagnosis using the diagnosis value.

Mode E (Drain valve property abnormality diagnosis)
Perform the drain valve property abnormality diagnosis depending on the magnitude of the tank pressure change after the leakage diagnosis completed.


I was initially thinking of using some resistors in place of the removed Pressure Control Solenoid, Drain Valve, and Purge Control Solenoid Valve. But with the added knowledge of this diagnostic check, I don't think this will work.

I'm wondering if a resistor in place of the fuel tank pressure sensor will help trick the ECM into thinking there are no leaks.

Unfortunately tuning the codes out is not really an option because I'm using the Accessport.

Any thoughts? Any help is greatly appreciated!

gunshed is offline   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

All times are GMT -4. The time now is 07:30 AM.

Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2020 Axivo Inc.
Copyright ©1999 - 2019, North American Subaru Impreza Owners Club, Inc.

As an Amazon Associate I earn from qualifying purchases.