Subaru dealership "cannot communicate with my car's ECU"
 

3 weeks ago I took my car in for service at my local service place to fix a check engine light issue. I already connected to my vehicles computer via OBD and my app Carista and the code was an A.C. code (sunload visor). I don’t have a clue about how to fix it.

Background: My vehicle is modified with a Supercharger, custom exhaust system, custom tune, and Flex fuel kit, and nothing else. Nothing that should prevent them from fixing the problem.

The local service place tried multiple times to fix it, they bought multiple A.C. sensors from Subaru but they both failed to fix the issue, they recommend I take it over to the dealership so they can fix it.

OK So 2 weeks I took the vehicle over to my local Subaru dealership. After running diagnostics multiple times and multiple ways they told me their computers “cannot communicate” with my car’s ECU. They have never seen it before. They said it could be due to one of my aftermarket parts, and that the way Subaru’s computer’s cannot read my vehicle. I told them ‘are you kidding me’ I just connected to it using a $50 OBD app’. They said theirs is different and if a vehicle has any aftermarket parts, it won’t read the ECU. They recommended I remove my supercharger and I then proceeded to laugh at them.

So now how do I fix the problem? They wouldn’t know, and couldn’t tell me.

Fast forward last week, I parked my vehicle in a parking garage and they lost my keyfob. Luckily I was able to Uber home to get my backup one. I purchased a new keyfob from Subaru. Today, they had to re-program my new keyfob. And the same exact issue cropped up. They cannot communicate with my vehicles ECU. They don’t know what to do. If I lose my backup keyfob, I am screwed here.

So has anyone else had this problem before? I have previously taken my vehicle to this dealership many times over the years for general service without any issues until now. All of a sudden their new Subaru “supercomputer” cannot connect to my vehicle just because I have a few aftermarket parts in it. It’s absurd.

Meanwhile I still have my check engine light on due to the AC sensor (sunload visor), and I cannot get my keyfob reprogrammed because they cannot communicate with my ECU.

What do I do here? Any advice please, I am stuck here. Maybe there is something wrong somewhere in my vehicle and that's the issue but I don't know what.

They're either giving you a load of BS so they dont have to work with your modified car, or the OBD2 port pins are messed up. These car do seem to have a weak OBD port, but it's an easy fix.

I thought it could be the OBD2 port as well, but today I again was able to connect to it using my own. So it doesn't seem to be broken.

And I don't think they are giving me a load of B.S. First their service dept couldn't diagnose and connect to my car. Then today, in an entirely different building, the parts dept. couldn't connect to re-program my keyfob. So two different depts. telling me the same thing? I don't think it's some conspiracy. I think it could be something wrong with my car but I don't know.

Anyone else have any Subaru dealership not able to connect to their vehicles?

Assuming their diagnostic software is looking for the original stock tune and can't find it. It's not that far fetched.

If it has ecutek tune, that might explain it

Could you try to reflash the stock tune to see if they could read it then and reflash back to your custom tune once the service is complete?

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it is an ecutek tune, how does that 'explain it?

good idea, ill try that

Ecutek will lock them out. It happened to my car as well

same i came in once for them to replace broken studs because i didnt have anything at the time to press studs out and they complained they couldnt confirm my ecu or some shit. the guy at the front desk told me to tell them to put "do not update ecu" on the notes next time i come in.

When my motor blew and was warrantied I was lucky because they gave up trying to reflash over ecutek tune and just replaced ecu lol

did not know this, learn something new everyday, i guess ill be flashing it to stock so they can do the work

Idk if that's a good idea with the supercharger

why not? well what do you think i should do then? i need my key fob reprogrammed. this is kind of important.

I would flash stock tune and have it transported. I've never heard of running a supercharger with a stock flash. Maybe someone else can chime in here?

what if i drove to dealership with my labtop. flashed it to stock there. have them re-program it. then i can flash it back to my tune. i think that may work.

i mean how bad could the car drive using the default with a supercharger anyways? it would still be drivable at least right?

I doubt it. Especially if you're running larger injectors. Your idea of flashing stock tune at dealership sounds pretty good imo

right until the car starts throwing misfire codes while they pull it into the service bay, and the tech attempts to go ahead and fix those codes...

just be honest with them about it, let them know what you're doing, and how the car will not be driveable while they program the key.

no, i dont have larger injectors. i have an automatic. supercharger, flex fuel kit.
custom exhaust system. thats it. i think it may even be drivable on lower RPMs. im not really sure. the tune came from Moto East. But that was three years ago. Should i email and find out? Are they in business still, does anyone know?

i know right, i need to make sure i communicate it clearly to them to not move the vehicle once the tune is back to default.

Contact xero limits. That's motoeasts new name. They'll be able to help you.

Unless you can get it at zero boost... It'll run lean. Probably. Check with your tuner maybe.

ok thanks i just did

i will, thank you

Driving it with a stock tune is what I'd be worried about more. Stock tune should be fine just to start up and let idle, just to get an OBDII reading.

I talked to Mike over at Moto-East (now Xero-Limit) because he was the one who did my tuning. He couldn't give me any explanation why the dealership can't communicate with the ECU. Nobody can.

But he said what I need to do is just replace my 3 bar MAP sensor with my stock sensor, then re-flash the tune to stock, and do this at the dealership so they can gingerly drive it to the service bay, do the work. then i can put back in my 3 bar map sensor, then re-flash it back to my tune.

Crazy right? Absolutely nuts I need to do all that just for them to fix my check engine light and also re-program my key-fob.

Back to really simple. Had a friend that my "good" reader would not work, but the cheep one would. It seems that the connecter in the car is not great. I used an extender cord with the good reader and all worked well.


Just a thought.

That does sound like quite a mess. I'd try an indie locksmith, i had one copy my current key to an aftermarket key (obviously doesnt help your AC issues)

the parking garage who lost my key fob had 3 locksmiths come. only 1 seemed capable of doing it. but his software did not work with subaru brz or something. not sure why not.

luckily i was able to uber home and get my only backup fob which im using now.

do you think i should replace my OBD2 port? Mike at Xero-Limit suggested that. But i was then able to use my OBD2 port and software (Carista) just fine to connect. Maybe the dealership requires a better connection? Who knows. Maybe I should replace it?

Just for fun do you have tried to read your ecu with techstream ?

no, no idea what techstream is, please inform

Not that is helpful due to the problems you currently have, but every Subaru will have a code for the AC Sunload sensor if you scan it inside a building. This is not a problem. If you put the car outside and scan it the code won’t be there. Do not try to “fix” this code.


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Techstream is the software toyota use for all is model, you can do anything with this like programming key etc, the only thing you cannot do is play with the odometer, im sure it's will work with the brz, if it's work with the 86 it's will work with your car,



For the cable with a copy of the sotware here : https://www.amazon.com/capital_auto-...=fsclp_pl_dp_9



You can find more recent software problably on this forum or on the web

my check engine light has been on for months due to the sunload sensor and my car is always parked outside. my car is never inside. not sure what your talking about. i scanned it using my own tool outside, it shows the ac sunload sensor. how does that have anything to do with being inside then?

thanks but i would have absolutely no clue on how to use that tool to reprogram my key and i would be hesitant in using it because who knows if i mess something up in using it, but thx tho.

That code will not turn the check engine light on. There’s something else causing it.


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To be fair you never mentioned where you scanned it but did mention your local shop tried to fix it. *They* would have scanned it indoors, so it's not unreasonable for him to assume it was scanned indoors.

Outside of getting it running the first time, it's an easy tool to use. You won't mess anything up by going through the key programming. Granted I haven't used it for that since I haven't needed to. I think @Opie might have though. We've used it to troubleshoot other stuff on these cars though...

well when i run the diagnostics for the check engine light. thats what the code returns. Code B14A1. Sunload sensor circuit. No other codes are shown except that.