I've got a P2096 Post Catalyst Fuel Trim System Too Lean (Bank 1) code tripping my CEL. It suddenly appeared during a long highway drive a couple months ago. Cleared it and it didn't come back for a while, but then came back on another long highway drive and persisted. Since my previous engine burned a lot of oil right before it died, and I got some catalytic converter efficiency codes (fixed temporarily with O2 spacers), I figured the catalytic converter was gone and so I just had a brand new OEM one put in (no O2 spacers). The code came right back. It drives fine, with no hit to fuel economy.

I can't find anything on this code for Land Rovers except a few random references with no resolution. Not sure what to look at next. I have a few data logs from my IID tool, but not sure what to make of them.

Here are the voltages from the bank 1 rear O2 sensor at idle. Doesn't look particularly lean to me?





I also checked the fuel trims, but they all look normal (in single digits).

Here's what I'm thinking:

1. O2 sensors are bad (likely rear, but not sure).
2. Leak somewhere in the exhaust manifold or gasket letting air in (would think it would push air out given the pressure?)
3. Leak somewhere after the MAF (why would this only trip a bank 1 code?).


Any help or direction would be appreciated!

 

During that graph, was that at idle, or while driving?

 

That was at idle.

 

Looking at the LFTF and STFT for bank 1, something stands out. Why is the LTFT positive if the STFT is mostly negative?








I checked bank 2, and it doesn't have this quirk.

 

At an idle it should be very flat from sensor 2.

 

An exhaust leak can and will cause this issue. Have someone stuff a rag in the exhaust tip, while you look for a leak. Did you Change O2's when you installed the cat?

 

These fuel trim readings from sensor 1, or 2? I get this is bank 1

 

Kept the same O2 sensors for now. The exhaust leak would have to be before the O2 sensors, so at the manifold, correct?

 

Yes on the leak. Here are my graphs for comparison to yours.

 

To rule out O2 sensor issues, swap them side to side. Both fronts are the same and both rears are the same. IF the problem moves with the sensors, then you need a new sensor. If the problem stays on the same bank, you will need to dig deeper.