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    1. #1

      Check Engine Light

      Hello everyone,

      I'm currently at a loss. We bought a 2015.5 with 86K. Everything looks great and we were (and still are) happy about it, but after about 120 miles after purchase the check engine light came on. The code was P2096 Post Catalyst Fuel Trim System Too Lean Bank 1. I called the dealership (not a Volvo unfortunately). They came back and said that an O2 sensor needed replaced (no surprise) and the thermostat as well (that code was not showing before, but it's their dime). They replaced them the next week. All was good and the exhaust smelled fine. Then again at about 120 miles the check engine light came on again with the same code! I checked, and there is indeed a new sensor. It's the one on the right side as you are looking toward the front of the car.

      Any ideas?

      Thanks!

      Donley

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    3. #2
      Junior Member tunedxc60's Avatar
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      Quote Originally Posted by sissomd View Post

      Any ideas?

      Thanks!

      Donley
      I would take it to the dealer or at least have someone (or a shop) connect to the car using VIDA to see what detailed codes are present. I have noticed the generic OBD2 codes don't always tell the whole story. Maybe your o2 sensor needed replacement or maybe it didn't - without using VIDA you really don't have the whole picture of what is going on.


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    4. #3
      Junior Member
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      It likely needs the catalytic converter replaced. Hence the code fuel trim post catalyst, It means the air fuel ratio after the CAT is incorrect indicating the CAT is not doing it's job. This component has an extended warranty I forget but its either 8 year 80k miles or 10year 100k miles.

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    6. #4
      Junior Member
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      Your dealer spunds like they made a common mistake. They assumed that because this code is trigered by the O2 sensor that it means it is BECAUSE of the O2 sensor. In reality, when O2 sensors go out they throw a different code or you can monitor their readings and see they are erratic.
      O2 sensors are pretty dumb. All they really do is measure the amount of oxygen left in the exhaust after it goes through the engine and then again after it goes through the catalytic converter. It sort of feeds a ninary signal telling the computer then engine is too lean (more air than gas) or too rich (more gas than air). Too lean seems to be much more common. Before the cat this usually caused by an air leak somehwere in the air intake system AFTER the mass airflow sensor (e.g. intake gasket, breakmin a hose, loose hose, etc.), but it can also be an small craxk in the exhaust that lets in a tiny amount of air around the O2 sensor. The latter can also be true for an after the cat O2 sensor...ironically, any crack is usually found at the cat to pipe joint OR in the O2 fitting in the pipe (where the O2 sensor screws in). It could also be, as Shaun notes, the actual cat.

      Good luck!
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    7. #5
      Junior Member
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      Idk man.. I had a P0420 code as soon as I bought mine(400mi in). I figured it needed a new Cat because the dealer said it was intermittent with the last owner. I got them down a few grand on the sticker price. I ended up changing the spark plugs, have driven 3500miles and haven't seen it since.

    8. #6
      Good info. Thanks. I'm going have it hooked up to a VIDA and see if they can give me any more specifics (and see how long the cat is under warranty). This weekend I'll have to check the plugs and wires and see how they look. I was under the impression that there were 4 O2 sensors on this vehicle but I can only find the three that are clustered together right by the block. Is there a fourth one? And if there is, where the heck is it?

    9. #7
      Junior Member
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      The necxt one would be post cat. down stream from it.


      Quote Originally Posted by sissomd View Post
      Good info. Thanks. I'm going have it hooked up to a VIDA and see if they can give me any more specifics (and see how long the cat is under warranty). This weekend I'll have to check the plugs and wires and see how they look. I was under the impression that there were 4 O2 sensors on this vehicle but I can only find the three that are clustered together right by the block. Is there a fourth one? And if there is, where the heck is it?

    10. #8
      Federal law mandates that auto manufacturer's replace emission system components for 8 yrs/80k. Arguable whether oxygen sensors could be considered an emission control component.

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