I threw two codes the other day, P0130(o2 sensor bank 1 sensor 1) and P2096(post catalyst fuel trim system too lean bank 1). I know that the first code is an O2 sensor, but the second one confuses me. From what I've read the P0130 could have been thrown due to an exhaust leak somewhere neat the cat. Can someone point me in the right direction before I dish out $180+ for a new Bosch O2 sensor. Thanks

 

Anyone? I need some advice, do I need a new O2 sensor or not.

 

What year and model is your car?

 

The P0130 is an indication of an open circuit for the front o2 sensor, while the p2096 is an indication of a rich condition on the rear 02 sensor.

Use your scan tool to monitor the front o2 sensor; with the car idling within a few minutes you should see the B1S1 voltage fluctuate at a fairly regular frequency between approx .2 to .8 volts at idle. If this is true the o2 is responding (you could still have an intermittent connection). If the voltage remains at .37 to .45v then perform a visual inspection of the front o2 wire make sure it did not melt on the exhaust or has corrosion in the connector.

The P2096 is an indication that the rear o2 sensor remains high during a period of deacceleration (fuel cut off) to test this one get the car up to speed and release the gas pedal, the ECM will cut the fuel for as long as you do not slow down so the RPMs approach idle. Be careful! have an assistant monitor the B1S1 voltage for the front 02, it should be a flat line at zero volts on the scan tool. If it is not then fuel is still getting into the combustion chamber during fuel cut off (possible cause leaking injector) If the B1S2 (rear o2) detects fuel when should not be any this code will set.

I would suggest trying these two checks with the scan tool before replacing anything. Also what the fuel trim value at idle for the LTFT parameter?

 

Interesting...

I just got the P2096 code as well but the Bentley manual is telling me that it measn "Post catalyst fuel trim system too lean (bank 1)". As the OP said the meaning of that baffles me. Based on your post frenchie, if a rich condition suggests that the engine is getting to much fuel (duh I suppose) a lean condition suggest a lack of fuel. But what would cause that? And more importantly has anyone else gotten this and found a solution?

 

You are correct about the Bentley manual. It states a lean condition for the 2096 code; Mitchell states a rich condition for the same code; one of them must be in err.

If the code means a lean condition check for exhaust leaks close to the rear o2 sensor. Please advise on the contents of the freeze frame (data that is recorded for the code to set) this information will give valuable insight into how the ECU tested for / determined that this condition exist.

 

For what its worth. When I got my P2096 two months ago, dealer replaced the post-cat O2 sensor but that didn't cleared the code. They spent another 2 weeks looking for the cause and eventually replaced the catalytic converter as a last resort. My Mini was still getting the P2096 after that, I took the car back from the dealer since they've had it for too long, drove it for a few days and the code disappeared. and never came back.

DeeMan
2002 Mini

 

The cat efficiency non-continuous monitor may have passed the test after replacing the cat (needed a drive cycle) maybe thats why the code went away.

A lean code on the post o2 can be caused by an exhaust leak close to the post sensor, or a cold o2 (the sensor will not produce a signal when cold) which would probably set a o2 heater code

It can also be caused by a lean air fuel ratio (which would set a fuel trim limit error for the front sensor)

A worn out cat (lean means that the cat is no longer consuming the oxygen but rather letting it pass out and seen by the sensor)

More information is needed; the fuel trim value for LTFT at idle and also at 2500rpm. Also the freeze frame data for the code.

Some manufactures use an intrusive strategy to test the rear o2; the ECU commands a rich condition when appropriate, then it looks at the response on the rear o2, with the expectation that it will go high or low as the case may be.

If the results are not as expected within a certain amount of time the code is set. Thats why the freeze frame is so important; it gives insight into the strategy that the ECM used to determine that a certain condition exist!

 

Frenchie you sound like a car doctor. Have you had this code? If so how did you fix it? Iv'e seen many threads on this P2096 and not one has an answer to the problem. Only speculative opinions. Someone somewhere has to have a difinitive answer. Where are you?

 

I have not had the code, however the conditions that can set the code have been documented by the manufacturer and each scenario has to be assessed on its own merritt!