Welcome to the North American Subaru Impreza Owners Club Sunday February 23, 2020
Home Forums Images WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC Technical > Factory 2.5L Turbo Powertrain (EJ Series Factory 2.5L 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. 
Reply
 
Thread Tools Display Modes
Old 04-07-2019, 05:37 PM   #1
Whitebomb
Scooby Newbie
 
Member#: 428667
Join Date: Aug 2015
Location: SF Bay Area
Vehicle:
2007 WRX Sdn
SWP

Default Barometric sensor malfunctioning

The sensor (attached to the LH secondary air injection valve) is fluctuating readings of atmospheric pressure between 14-18 psi. I plugged in a new sensor and it held nice and steady at 13.9 (this was at a higher elevation fyi). So I am assuming itís not the wiring causing the issue.

Can I clean/refurbish my sensor in any way or is a replacement a must?

Worth noting that valve was stuck open recently and I installed blockoff plates. I donít fully understand if the corrosion in the valve indicates corrosion in the sensor.
* Registered users of the site do not see these ads.

Last edited by Whitebomb; 04-08-2019 at 03:16 PM.
Whitebomb is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 04-09-2019, 02:40 PM   #2
07wrxhaweye
Scooby Newbie
 
Member#: 495306
Join Date: Dec 2018
Location: New Bedford Mass
Vehicle:
2007 Wrx Tr
World Rally Blue

Default

Is there any way to check the wiring on these sensors as well? Ive been battling a P0244 code and already replaced the solenoid with a known good one. I have both the Torque app and OBD link app and neither are showing me a baro reading. I'm almost positive its something with the sensor or something in that area cuz thia all started after i changed my starter last year. If anyone can help me with any kind of diagnostics to determine if the sensor is truely bad or if its a wiring issue i would greatly greatly appreciate it.
07wrxhaweye is offline   Reply With Quote
Old 08-13-2019, 01:43 AM   #3
FPV
Scooby Newbie
 
Member#: 505239
Join Date: Aug 2019
Default

Quote:
Originally Posted by Whitebomb View Post
The sensor (attached to the LH secondary air injection valve) is fluctuating readings of atmospheric pressure between 14-18 psi. I plugged in a new sensor and it held nice and steady at 13.9 (this was at a higher elevation fyi). So I am assuming itís not the wiring causing the issue.

Can I clean/refurbish my sensor in any way or is a replacement a must?

Worth noting that valve was stuck open recently and I installed blockoff plates. I donít fully understand if the corrosion in the valve indicates corrosion in the sensor.
Where did you get the new baro sensor?
FPV is offline   Reply With Quote
Old 02-11-2020, 03:24 PM   #4
08STIER
Scooby Newbie
 
Member#: 511527
Join Date: Feb 2020
Default

Maybe no one cares, but this looks like a sadly neglected thread. If we really want to get to the bottom of this, we would need to start compiling a set of either voltage values (or resistances) as a function of altitude. Maybe in the manual...

Based on what I see from the diagnosis part of shop manual, the following pins
exist:
1 = should be 4.5 volts or more. The circuit is shared with the electronic
throttle.
2 = Connection to Engine Control Module, should be R >= 1 MOhms, relative to
ground
3 = ground for sensor, should be less than 5 ohms at the harness. This ground
is shared with the MAP, electronic throttle, and coolant temperature
4 = ground to valve solenoid
5 (missing, not used)
6 = power to valve solenoid from control relay

My interpretation is that the barometric pressure sensor is effectively a variable resistor between the ground (pin 3) and pin 1. The barometric pressure sensor (variable resistor) acts as a voltage divider. This is why the Pin 2 is the ECM, engine control module and is likely using pin 2 to measure the voltage...hence the comment that it should be 4.5 volts or higher (dependent on atmospheric pressure). Then pin 2 reports this value in some look up table to modify the engine parameters.

If we want to crowd source this information, we either want a table of
1. resistances between pin 2 and 3 (ground) for various altitude.
2. or turn the key on (engine off)
and measure the voltage at pin 2 with the key on (measured at A27, connector B134 of the ECM).

Any easy way to do this, would be:
A: If anyone who lives in the bay area and wants to go to Lake Tahoe for the weekend, could measure resistances at different altitudes....or
B: If someone has a spare that is good, but has a stuck valve that I can borrow, I could try simulating altitudes with a bicycle pump and convert psi to altitudes. My sensor is bad, so I wouldn't trust the data.

Last edited by 08STIER; 02-11-2020 at 03:29 PM.
08STIER is offline   Reply With Quote
Old 02-11-2020, 03:58 PM   #5
Haevn
Scooby Newbie
 
Member#: 495950
Join Date: Jan 2019
Location: Augusta, GA
Vehicle:
2011 WRX
WRB

Default

i have a spare off the driver side valve from when i did my air pump delete, had to use the passenger side one and cut the sensor off so i wouldn't have a code
Haevn is offline   Reply With Quote
Old 02-11-2020, 05:08 PM   #6
08STIER
Scooby Newbie
 
Member#: 511527
Join Date: Feb 2020
Default

Thank you Haevn! PM sent.
08STIER is offline   Reply With Quote
Old 02-11-2020, 11:34 PM   #7
Trob
Scooby Newbie
 
Member#: 503820
Join Date: Jul 2019
Default

You can cut the sensor off the top of you working valve. I deleted my secondary air and we just cut the sensor off the top of the value. Then zip tie and your off.
Trob is offline   Reply With Quote
Reply

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 12:57 PM.


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.