Check engine light and Traction light on.
 

My 2014 Subaru Brz limited has only 1 mod and it's a drop in k&n air filter. After installing the filter I drove the car for a week without any problems and then I had my check engine light and traction light on on my way back to work. I got an OBD scanner and got the following codes:
P0171 - System too lean Bank 1
P117B
P1170

I took out the filter and reassembled it into the air box yesterday and also cleaned the maf sensor with CRC maf sensor cleaning liquid. Disconnected the battery and reset the ECU. Took it for a test drive and no problems.

Today when I started the car and before going a mile the check engine light and traction light is back on. Traction light goes away after some time and
comes back again. Check engine light remains on and stays on.

What do I do to fix this? I have no idea what's happening as I'm a noob to the car scene. If anybody can advise that would be great. I live in the waterloo region in canada and would love to take the car to a good mechanic in the region if anybody can suggest one for me please.

Try putting the stock air filter back in and see? Did you knock something loose? Any images of the engine bay?


All seem like fuel injector codes.

Hello ser1alchill3r and welcome to our forum - :clap:

It appears that you have done the easy things. Considering your limited knowledge of that car, I would recommend that you take it into a shop and have them fix it. Meanwhile you may wish to look up those codes on line and follow their leads to look for a bad connection that would effect an injector.

I hope you get er fixed soon.

Thanks @humfrz.

I will be getting a new stock air filter tomorrow and will reset the ecu again with stock air filter and see what happens.

How many k? How long have you had the car?

113000 kms. I bought the car recently when it was at 100000.

OK, also make sure you have the MAF plugged in proper.

Ignition coil, most likely cyl #1

Hello, why do you think it's the coil pack? OP seems to have his CEL on right after changing his air filter, so it must mean that his air filter is the problem, no? I'm not trying to be rude, I am genuinely curious because I have the same problem :lol::lol:.

Might just be a coincidence. Coil packs can be a common issue on the platform, especially for the early models (MY13 and MY14) before the coil pack was revised

If the symptoms are known, it's worth checking.

At 100k km, may be spark plugs based on service internal. Though if the car was always NA, spark plugs usually are pretty clean.

I have no idea what's going on. So I'm going to take it to a subie mechanic tomorrow. Hopefully it's nothing bad. I'll keep you guys posted. Thanks a lot for pitching in with your honest opinions.

A very quick search on those codes came up with the below thread among others. Sounds like it is an air leak somewhere. Did you undo any hose clamps when changing the filter?

There is also someone who's battery died and the low voltages were tripping codes like that. More likely an air leak in your intake tho.

https://www.ft86club.com/forums/show....php?p=2128963

Check engine light and Traction light on.
 

The behavior of warning lights and obdii codes. Yes I agree it’s not obvious and there are certainly other possibilities ( for a bank to run lean, can be too much air or too little fuel in normal thinking, I think it had to do with short/long fuel trim and in a particular situation that our car seem to get into. The problem completely went away after replace cyl1 coil, in my particular case. Ymmv

Ps I too checked for leaks, fuel supply etc, until noticed a thread where cyl1 coil often fail on these cars prob due proximity to exhaust header.

I booked an appointment on Thursday with the mechanic. I dont think it's the coul pack cos I dont have a single misfire as per the obd scanner. However my LTFt and STFT are off the charts.