HELP! CEL P2096 0031 0032 0034 and P0021

05 Legacy GT MT, 25K miles.

 

Car is throwing P2096 0031 0032 0034 and 0021. Has been to the dealership twice and they don't know. Reset ECU 1st time and changed oil 2nd time (said it was sludge, I'm calling BS). They confirmed the plugs / wires / injectors weren't bad. What could this be!!! Its already 1 month out of warranty and its running like a Dodge Neon .

 

Could it be the OCV or VVT sensor? THat would explain the 0021 but why would 2096 show up? I added Fuel INjector cleaner along with Octane booster and a fresh tank of 93 to confirm that this wasn't related with bad gas. Anyone have any ideas??

Take out your OCV's and give them a good clean: http://legacygt.com/forums/showthread.php?t=18887&highlight=OCV

 

It should cure the P0021 for a while at least, until it starts sticking again.

 

P2096 is the rear O2 sensor and is often caused by an aftermarket DP, if you are still stock you probably need a new sensor.

 

P0031 is your front O2 sensor http://legacygt.com/forums/showthread.php?t=45262&highlight=P0031

 

Hope that helps.

Thanks Phil - am going to clean them over the weekend and give her a try.

 

Does anyone know if the msifire codes are related to P0021? I.E. would whatever is causing the P00021 also cause misfires? On 3 cylinders?

He means codes P0301, 0302, 0304 - those are misfire codes. If they are then I bet on a bad fuel injector.

Yes, it can do. The OCV's get stuck wide open, so the inlet timing is off by almost 30 degrees, therefore causing the bad idle.

Yes that is correct Rao - P0302 303 304 and P0021 and P2096 (possibly related to the fact that I put fuel injector cleaner in my last tank?).

 

I am going to try to run some data logs to get to the bottom of this (see if OCV valve duty is within range). Will upload and let know my results. Thanks for everyone's help!

On a similiar note .... I reset the CEL last night and my car idled fine and ran fine (albeit a noticable hesitation around 3500K) for about 25 miles, before it started idling funny / hesitation and the codes came back up. Based on this, would the OCV still be suspected or would the problem be ECU-related? A mechanical problem like a shut OCV valve shouldnt' just go away when I clear the CEL ....

Guys, this is really weird. Now the codes being thrown are P0301 302 303 304 - misfire on all 4 cylinders. P0021 isn't coming back up. Any thoughts on what this could be?

Really REALLY bad gas, or a lot of water in what you have. Put in three bottles of yellow bottled Heet (methanol), at least.

 

Fuel pump.

 

MAF sensor bad/dirty.

 

Big leak pre turbo, post MAF sensor.

To give everyone an update - I cleaned the OCVs to no avail. Ordered new ones, slapped them in, and now the car is back to its glorious old self again. Thanks for the pointers!

I'm going to have to bite the bullet and order new ones too

Really REALLY bad gas, or a lot of water in what you have. Put in three bottles of yellow bottled Heet (methanol), at least.

 

Fuel pump.

 

MAF sensor bad/dirty.

 

Big leak pre turbo, post MAF sensor.

My car has been sitting for over a month with the same tank of gas (less than a 1/4). I've been starting it up ever week (have to charge the battery) but I keep getting the P0031 code even after clearing the code. Can it be just from the gas and if I put in new gas, will it go away? I'm not sure if these sensors only put out a code if they fail or if they sense something.

 

I'll check the resistance of the sensor but I forget what value it's supposed to be.

Hi Guys,

 

This is my first Post I realised I spend allot of time on this forum picking all of your brains but never tried to help out myself.

 

I recently had a p0021 code and after looking here removed my ocv and cleaned it first because it was free and easy todo. Only one bolt then pull.

 

The problem went away but then after about 2 days it came back again. So i fugured it could be my air mass meter. I took the intake tube off and sprayed with maf cleaner and again car was ok for two days and then the disco reappeared on the dashboard. (Obviously subaru think and ecl is not enough they have to throw in two more) So I was at this point at my wits end I considered buying a new ocv valve but they are pricey very pricey.

 

Then i came a accross a thread saying to change the Oil I didn't think this would help but there is no harm in doing this I thought and whilst I was at it I changed the plugs and the air filters etc

 

Now we are 3 weeks on and the car is running 100% sweet with no lights and feels brilliant.

 

Just thought I would throw this in there hope it helps someone