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Diagnostic code / O2 sensor problem

8K views 3 replies 4 participants last post by  pjcampbell 
#1 ·
Hello all. First post on the forum.

I've got a '05 outback XT 2.5L 4 cyl. manual transmission with 75,000 miles on it. Earlier this year the check engine light came on and I had the following code pulled:

P2096 Post Catalyst Fuel Trim System Too Lean Bank 1

My tech found it was the O2 sensors and I ended up having to replace all of them before the check engine light would stop coming on.

It's been fine for about 3 months but now the check engine light is back on, with the same diagnostic code. I had my guy check it out and all the O2 sensors are working fine and behaving properly. He suggested I take it to the dealership because it might be an issue with the electronic control unit. I know this can be a pricey fix if it is the issue.

Any ideas on what may be happening that would cause this code to happen if the O2 sensors are ok?

Thanks for any info you can provide!

amac
 
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#2 ·
I doubt it's the "electronic control unit", if what is meant is the engine control module. They are quite robust and rarely fail.

However, the P2096 is not necessarily indicating a fault with the sensor itself. The code could be caused by another sensor malfunction, or a leak in the exhaust or intake systems, low fuel pressure etc; i.e. anything that would cause this sensor to indicate a "too lean" condition.

Incidentally, it seems that the use of genuine Subaru O2 sensors, at least the front ones, is usually required; it's reported that aftermarket parts don't always perform properly. Do you know what the order of replacement was earlier this year, and what brands were used? This might be important information if you bring the car to a Subaru shop (dealer or specialist).
 
#3 ·
O2 Sensor light

Hello! I have the same year and make Outback, although automatic transmission. It has been a couple years, but I have the same problem with the code P2096 coming on and everything reading fine. I wondered if you ever figured out what was causing the code to trigger? Would appreciate your help. Thanks,
CindyR
 
#4 ·
Any ideas on how to fix P2096, or ideas on what to try next on a 2005 2.5 (stock) with 160k miles. Have replaced rear O2 sensor.

Local Mechanic has indicated that it is only the 5th O2 sensor that is reading lean and seems to be intermittent.

I should add that it's been coming on and off for a while now. I can drive maybe 1-2k miles and then it comes back on. Last thing that local guy did was to clean out the TB which helped with low idle, and seemed to make the code go away for longer than normal (few k miles instead of few hundred miles).

I doubt it matters but I've been running 91 ethanol free for a while now.
 
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