All Wheel Drive Auto: Independent Seattle Subaru Service


Diagnosing Subaru Problems

Subaru Select Monitor

Through the years a lot has changed about diagnostic procedures and more importantly the tools in which are used to help a Technician reach the right conclusions.   Pictured below are the three different Subaru Select monitors that have been in use.  The current version is part scan tool and part pc based platform that also gives us the ability to re-flash a Subaru vehicles ECM (Engine Control Module).  This is an important distinction between us and some of the other shops around, we believe in staying current with the diagnostic tools and procedures to keep you Subaru running its best.

Some Subaru problems pertaining to performance and check engine lights have been addressed with a logic update much in the same way a bug in a pc is resolved with a software update.  This is true of some of the other systems in the car as well.  We believe this is a very important service to offer our customers and a great way to truly fix problems other shops may not be able to take care of.

The Subaru Select Monitor “the original” was capable of reading codes, and one line of data could be read at a time as well as a series of lights to indicate function of various components.

Subaru Select Monitor I

The Subaru Select Monitor II came out in time for OBD II (On Board Diagnostics two) and is a big step up from the Select monitor, being able to read multiple lines of data, tap into other systems the ability to graph sensor readings and it has a built in volt ohm meter with digital oscilloscope.  The Subaru select monitor II has the ability to re-flash the ECM as well with the proper flash cartridge.

Subaru Select Monitor II

The Subaru Select Monitor III is part Pc and part scan tool or pass through device.  The Scan tool has a built in flash memory card and can be used as a “flight recorder” meaning sensor readings can be recorded over the course of a test drive and later uploaded to the PC where the data can be looked at by the diagnosing technician. The new version of the Select Monitor also allows the technician to graph sensor data,  look at multiple lines of data (more than ever before) Reflash the Vehicle’s Computer, program remotes and is a great needed tool to diagnose modern Subaru problems.

Subaru Select Monitor III

We believe one sign of a great repair shop is staying current to offer the best service possible.

Thanks for reading



31 Responses

  1. Do you what could be the cause of very HIGH oil pressure? I am reading 100psi on the block. I just got done having the heads redone by a very good machine shop that does Subaru and I’ve installed Felpro head gaskets and made sure they were on the right way also. How can I verify that oil is getting to the cams on the cylinder heads?

    1. Hey Mark,

      Blockage most likely. Very minimal info such as what year and model. But clogging in any of the VVT system could be a cause. If the pressure is truly that high do not continue to run the engine until you have sorted it out which is going to require removal and teardown and a great time to scrap the HG you used for Six Stars.


  2. Hey there. I have a 2017 Wrx sedan. When i bought it in Puyallup, in 2020, the P0016 code lit up. Abs, traction control, hill assist, cruise control, and check engine light are on.
    Subaru Dealership in Wenatchee said to replace camshaft. But it drives perfectly. So I didnt. Subie Independent in LA said timing chain. So they replaced my timing chain & ecm sensor. The code is still popping up but they said it’s reading now as a history code rather than a current code. They said they were just running through all possible diagnostics and were going to replace the computer but I had to move back to Washington before they got the space & time to do it.
    Any ideas?

    1. Hey Zoey,

      Tons of ideas, all that need to be proved or disproved. The 2015+ FA20 requires very real knowledge to be able to accurately diagnose. As far as history codes vs live data if you as a driver fails to repair the car fairly quickly after the original fault occurs the ECM will need to be replaced as the learned values of the VVT can not be unlearned by the ECM. If learned values ever exceed or get close to being out of range the ECM will need to be replaced

      This is lost on a lot of shops including the Dealers if they don’t read up on 02-163-16R. Which is most likely what happened here.

      So even if the chains were the problem, and they were repaired, if the Shop making those repairs did not also evaluate the learned values piece the problem while technically fixed mechanically, it will still set a fault as the ECM is unable to relearn the new VVT values post repair.

      Sorry I dont have better news


  3. Hi Justin, my son bought a 2014 Suburu Tribeca and his transmission went out so he had that replaced and now the mechanic test drove it and it will only do 25 mph down the road on the analyzer it says po700 transmission control system(mil request), po715 turbine/input shaft speed sensor circuit, po734 gear 4 incorrect ratio, po756 shift solenoid b performance or stuck off can you tell me what this means

    1. Hello Trina,

      There a lot of possibilities, but if I had to guess it has one or more damaged solenoids in the used Transmission that was just installed, I am assuming its either used or an aftermarket reman.


  4. Hi Justin,
    I have a Subaru 2008 Forester. The passenger and rear seat windows can no longer respond to the driver side control to raise or lower them. The controls on each door window do not do anything either.
    The driver’s side window works well.
    I couldn’t find if a fuse would be out when I looked into the owner’s manual.
    Nothing I’m aware of has impacted the car or battery that should cause wires to break,
    Is there a code reader that tells what may be the problem?
    Thank you for your consideration.

    1. Hello Peggy,

      I am sorry for how long it has taken to get back to you, it’s been a very trying couple of weeks at our tow shops.

      Anyways, it sounds lie maybe the window lock button on the master window switch has been depressed? This allows you to control if your kids or captives can open the windows.

      If that is not the case most likely the master widow switch has failed, but it would need to be removed and tested to confirm.

      Hope this helps, but check that button first.


  5. 2004 outback frequently loses power to drivers door, both mirrors, all windows, power ,lock works but won’t open other doors. passenger door lock still ok. Passenger windows not. days later everything works again. Slaming door doesn.t help. Where is the connector plug? In door? Door was removed for body work. Previous owner gave up on it. Ground in door ? ground at fuses ? Everything else works. We don’t like to lower the windows as they may not raise again. Any clues? Ideas ? Geo.

    1. Hello George,

      That is probably some broken wiring where it travels through the door pillar to the door. I would start with looking there.


  6. Justin… my name is Mark from Spring Hill fl. I’m looking at a 2015 Impresive. My friend tells me when hes driving it the a.c will be cooling normally then it will start to warm up a little till he turns it off then back on then itll cool very well and may for a while. Then itll start warming up again. I replaced the expansion valve vacuumed it then put the required amount of refrigerant in it.
    Sitting at an idle it cools great. Only when hes driving does it periodically warm up. I thought it could have something to do with the sun season so I taped over it with electrical tape and he said it doesn’t warm up as often as it did but still does it.
    What do you think? My email is . any advice will be helpful

    1. Hey Mark,

      Your not mentioning if the AC is being commanded on by the ECM and not coming on or is and isnt when the Ac stops cooling? Without that info one cannot begin to diagnose the issue. What are the Line pressures when it stops cooling?

      All that is needed info to diagnose the concern.


  7. Hi Justin you are one of the few trustworthy mechanics, hope you are having a good day, question my rear wheels are no longer getting power on my 2014 4 cylinder Outback, no codes, but when I run the all wheel drive power percentage app it shows power is going to the real wheels but I know it is not by the way it drives, front wheels spin on hard acceleration and turns, I mean it is just so obvious the real wheels are not getting any power at all. 135k miles and way back when I used to get a AT overheat light so I took it into the dealer at 75k miles and they said nothing is wrong with it, but I made them change the fluid anyway since then no more light, I know there used to be in older Subarus a fuse you could pull to make it front wheel drive only, but I do not think my model can do that right? Any advice before I take it in to the dealer for a former mechanic turned nurse?


    1. Hey Brett,

      So one thing to check might be if the brake calipers are sticking?

      But if the AT Temp light came on there should be a code set? Last time and this time


  8. So my Girlfriend just bought a 2008 Subaru Legacy but about half way home from the dealer her AWD light came on. it goes out whenever she shuts the car off.
    she has taken it into a few places to get diagnostics done but no code ever comes up.
    everything seems to run fine but after driving for a few minutes it will come back on.
    any suggestions?

    1. Yes,

      To take it a shop that knows Subaru and can perform a proper diagnoses including but not limited to having the proper Subaru Select monitor that can actually communicate to the Control Module.

      That’s just the only advice that will yield any type of results.


    1. That there is an issue with the Clutch Duty Solenoid circuit, that will need to be diagnosed locally by someone who has the car in front of them and the ability to perform tests.


  9. Hi Justin I just got a code 1093 on my 04 Baja Turbo, # 2 TGV stuck open. Is that the drivers or passengers side? Thanks in advance for your help! Your the best!

  10. Hi Justin My 2002 legacy 2.5 has a problem that my mechanic can’t figure out.When you pull up at a stoplight the car dips in rpm’s and begins to run rough,then you have to put it in neutral to smooth out the engines idling,any suggestions what this might be?thank you very much for being the SUBAGURU

    1. Hello Cliff,

      Thee are so many possibilities its tough to narrow i down to one thing it may be.

      Sticky valves or drooped guides would be the things that Techs that dont know Subaru to well would overlook or not know about however.


      1. Thank you for your help. Sounds like I will drive down to see you guys during the week.This is one of the last problems to solve.Bought it used as per your very sound advice, and am fixing it up.Next time I will just buy one of your AWD used cars and save myself alot of worries.

  11. I had a rear wheel hub replaced on my 2008 Outback with 175,000 a few weeks ago.Shortly there after the ABS light came on, then I noticed the err 55 code in the odometer window. I cleaned and repalced the speed senser thinking it had a bad ground. Code came back. repaced the sensor.The code is back again.Today I desconected the batt.and depressed the brake peddal a few time and reconected the batt.In an attempt to reset the ECM.I would be to concerend about the ABS light on but my wife screams about the fact the cruse doesn’t work then the light is on. She drives about 35,000 miles a yr.Where do I go from here if that code comes back.Thanks Paul

    1. Hello Paul,

      You never mentioned what ABS code was set?

      If its related to the same corner the hub was installed maybe something has gone wrong with that install?


      1. err 55 shows up in the odometer.when my mech. ck for any other codes , there were non. He said he had a fuf time getting the hub off. It showed signs of getting real hot. Discolored.When my wife gets back in town I can have him ck again. Thanks Paul

  12. Hello, I found your web site @ google and i have read a few of your other posts. I like what u wright! I simply added you to my Google News Reader ;). Keep up the good work . Look forward to reading more from you within the future.

  13. Hey Justin,

    Thanks for sharing, I wondered if independents could work on the newer cars thanks for showing me its possible.

    Dave Dubois

  14. Thanks for explaining the differences in the scan tools used. You have demystified the system and added a new level of respect that I feel for what you do, for me and my beloved Subaru!

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