Welcome to the North American Subaru Impreza Owners Club Tuesday August 20, 2019
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
Go Back   NASIOC > NASIOC General > Newbies & FAQs

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.
* Registered users of the site do not see these ads. 
Thread Tools Display Modes
Old 07-16-2019, 06:57 PM   #1
Scooby Newbie
Member#: 504298
Join Date: Jul 2019
Location: Eastern, WA
2006 WRX Limited

Default 2006 WRX Low/No Boost Diagnosis

To start it off, I just bought my first WRX a week ago and am new to working on them. I'm an engineer and have built several naturally aspirated vehicles, however, so feel free to hit me with some technical info, haha. This is my first post and I appreciate any input and direction I can get.

Anyways, my car is a bone stock 06 Limited with 150K on the clock. I guess the only "mod" is the OEM? MPa boost gauge. I know the high mileage will obviously come with increased risk, but I got a super deal on it from the original owner, and won't be upset if I have to put a bit more money into it to keep it running strong. I have all of the maintenance records; oil/fluid changes on/ahead of schedule EVERY TIME since he bought it new; Water Pump, Timing Belt, Clutch, supplemental components replaced at 102K. Has been running the dealer "recommended" 5w30 oil the whole time (I changed to Rotella T6 5w40/ Genuine Filter the day I bought it)

Before purchasing the vehicle I knew the check engine and blinking cruise control lights were on. The owner said it was due to a faulty O2 sensor, and my OBDII scan "verified" this prior to purchasing, throwing the following codes in order:
- P0131 [Oxygen Sensor Circuit Low Voltage] CONFIRMED
- P2444 [Secondary Air Injection System Pump Stuck On (Bank 1)] PENDING
- P0410 [Secondary Air Injection System] PENDING
- P0031 [Heated Oxygen Sensor Heater Control] PENDING
- DTC P1153 [HO2S Insufficient Switching Bank 2 Sensor 1] CONFIRMED

Upon erasing the codes, the Check Engine and Blinking Cruise lights did not turn off. I took it for a 20 min test drive and re scanned. This time it only threw these codes:
- P2444 [Secondary Air Injection System Pump Stuck On (Bank 1)] PENDING
- P0031 [Heated Oxygen Sensor Heater Control] PENDING

I've put about 300 miles on it now, just fueled up for the first time (Shell V-Power 92) and have re scanned every day since owning it... no new codes.
BUT, here's where my lack of experience with these cars, and boost in general, really shines lol:
Although it seems to drive and run great, I was unaware that only pushing about 0.015 MPa (2 PSI) of boost is not normal (I'm an idiot and should have run the conversion on the spot, as I'm not familiar with MPa for boost, but knew that 11-12 PSI or higher is standard for these cars). It wasn't until I got home and did the conversion that I started going OH ****!

Upon looking at about 50 unique threads across the interweb this week, on all sorts of similar issues, I can't find anything with the exact problems I'm having that is actually well documented.

This morning I turned it on and let it idle for about 5 minutes at ~70 F outside temp, came back and noticed there was a small amount of light-colored smoke coming from the exhaust. I gave the gas pedal a 10s draw in neutral from idle to 3K RPM and slowly back down. The smoke immediately went away. I drove it around for an hour or so, let it cool down for another 2 hours while I horrored over all the ringland failure threads and went back out for a cold start. I let it idle for 2 minutes, shut it off, and quickly pulled the filler cap... no smoke at all here. Started it back up with the cap off and could feel the exhaust coming out, but there was no smoke.

So what else have tried?
- Cleaning the MAF with CDC MAF Sensor cleaner and no direct contact with any of the fragile components (slight increase in performance, but no change in boost pressure)
- resetting the ECU by pulling the negative battery terminal and holding the brake for ~30 seconds (no change)
- took it to a local Subaru-specific Tuning shop for a more in depth scan (same codes, but the owner did mention that he is not hearing ANY turbo noise at all. He stated that it is safe to drive, but is basically just running as a NA car right now. Like I said, I've never had a boosted car, but I am able to see 2 PSI or so in 3rd, 4th, and 5th gears, so why no spooling at all? IDK)

I know there's more to try out, but I just wanted to get this thread up as I have the following things in process. I will keep updating as these tasks are completed:
- ordered OEM Denso MAF, AFR(Front O2), Rear O2 sensors for install
- taking back to the specialist for a compression and leakdown test tomorrow
- ordered a boost leak tester to try that (BUT I'm not hearing any leaking sounds, at least not noticeable ones, so I'm not sure this is the issue)

Sooo, once again, I appreciate any insight you all can give me on this issue and am happy to answer any questions you may have. Thanks in advance!

* Registered users of the site do not see these ads.
paintchip is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 07-17-2019, 06:32 PM   #2
Scooby Specialist
Member#: 251046
Join Date: Jul 2010
Chapter/Region: MAIC
Location: Mostly at my home
2004 WRX Wagon
Stage 5.1.2a.2


Hey man... good job on the post first of all. Glad to see a help post where someone is actually helping themselves.

The fact that it's not even making the wastegate spring pressure amount of boost (I forget what the stock spring rate is... 6-8 lbs.) points me in the direction of the turbo. Either the wastegate isn't closing all the way, or the turbo isn't spinning or something. So my first suggestion would to take the turbo off and look at it. Leave the wastegate actuator attached at first so you can see the arms position with relation to the wastegate being opened or closed.
bdubblu 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 07:08 PM.

Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2019 Axivo Inc.
Copyright ©1999 - 2017, North American Subaru Impreza Owners Club, Inc.