Model: 2006 Jaguar S-type R
Mileage: 123k miles
Last past smog : 119k miles

Hello Jaguar forums.

I've posted on here in the past about having a lean bank 2 code p0174. I swapped the top O2 sensor and it looks like it I got it to go from fault to pending. But won't be surprised if it comes back. So fast forward today and I'm now getting a lean bank 1 code p0171 along with both bad cat codes. I'm not sure if they are related but I thought I should mention it anyways. I've read through the service manual and tried to figure out my lean problems with no luck. I've checked the LTFTs and they were both showing around 15 plus and jumping up and down so not sure how accurate they are. I performed a smoke test on my vacuum lines and found no leaks, along with a smoke test in the exhaust and found no leaks. My only other guess is fuel injectors. I'm willing to take the injectors out, but it's a lot of work so I'd like some input on if that's a common problem before performing that task. Any advice would be highly appreciated. Thanks.

 

first try checking your fuel pressure . for primary and secondary pump pressures ,
and replace your fuel filter first .
doubt it will be bad injectors on both banks . normally one may fail ,
but unlikely to be all bad at that milage .
mine tested perfect at similar km's

 

as for the cats mine were shot/clogged at less milage than yours .
and i recommend upgrading/replacing them . it gives your power back .

 

Okay thanks for the advice. I just ordered a fuel filter and going to check fuel pressure. I checked the pressure a while back on my obd2. But I'm assuming you mean a physical test? Also I live in California which has strict smog codes. Do you think I'm better off buying aftermarket CA cats to cut/weld or buy oem jaguar cats. The only oem ones I can find are uses low mileage ones which I feel will make the same problem down the road.

 

For what its worth, I've had a thread going on this lean code issue for the past couple of weeks, and I've been fighting the 0171 and 0174 for years on my 2005 s type 3.0 California car. Its ridiculous. And from research, I see hundreds of archived threads about these lean codes over the years. I just replaced my injectors last week in an effort to cure this issue. In my battle with the codes, I have smoke tested the car to find no leaks, replaced mafs twice, fuel filter, air filter, o2 sensor on bank 2 (because in my case that was the side that always comes up lean first), done all the plugs and coils, done the imt rings...and after doing the injectors, I still have 0171 and 0174 that go pending , but if left alone for a day or so, they turn to hard codes. I also have to pass a smog for renewal and this is in my way.
My lltfts roar up to 19.5 at idle and go down with throttle, while the stfts seem to correlate directly to throttle demand. Everybody says its a vacuum leak..or...any of a dozen other things. Very frustrating. My thread is titled fuel rail pressure or something like that if you want to read some helpful advice from some who responded to me.
I wish I could tell you how to solve it, but more than that, I wish you could tell me how to solve it.
FYI.. you probably already know this, but in California, it will pass smog as long as no cel is on, there are no hard codes (they don't care if you have a hundred PENDING codes, and all readiness monitors complete with the exception of evap. You can pass with evap and comp 1000 incomplete.

 

Damn sorry to hear you're having the lean problem. I'll take a look at your forum. I've been fighting the p0174 since I bought the car and now the smog codes are coming up. Not sure if that caused it or it was a coincidence. Luckily the car passed smog a few months back so I'm good on that. Just want to solve these codes.

 

did you mean this one ?

https://www.jaguarforums.com/forum/s...ectors-194976/


some good starting points for diagnosis any way .

also ; dont rule out a split EGR pipe or dirty sticky EGR valve ,
although they should have there own DTC , early stages often will not ,
and can cause this issue ,
and a smoke test will struggle to show this up .

 

Be sure to follow the advice in many threads to find whether the car has an air leak or not. Chasing the down the wrong paths having failed to check is a PAIN.

 

Hey everyone. I have an update on my car. After replacing the fuel filter. I decided to take it to a Jag specific mechanic to get a more detailed diagnosis of my lean/cat codes. He's thinking it's either clogged Cats or possibly injectors (or both) that's causing the issue and the lean code is correlated with the Cat codes. He wants to start by putting new cats on from the dealer to get more accurate fuel trims. But I assume he's going to come back with a high price to get the OEM California direct fit Cats for the car. So I was wondering if I can pull my Cat assemblies off and bring them to an exhaust shop to weld these on? I'd appreciate any info on this topic. Thanks.

Link To CATS