Hey guys, new member here, this will probably be my first post of many. Here's my new member post: https://www.jaguarforums.com/forum/n...cticut-111758/

Ever since I bought my X-Type, I've been having a couple issues which I'm assuming are related to the codes above.
-Poor acceleration (don't know if it's because the car is so heavy or not)
-Bad fuel economy. I'm getting 10-11 mpg combined highway/town driving.
-Stalling after braking downhill occasionally. I have to turn off the ignition and restart the car. I can feel the power brakes and steering start to fail right before it happens.

P0174 - System too lean (Bank 2)
P0158 - O2 Sensor Circuit High Voltage (Bank 2 Sensor 2)
P1638 - ???
C1175 - ???

From the research I've done, it seems like the poor acceleration and bad gas mileage are from a downstream catalytic converter O2 sensor related problem, which would be P0158, which would suggest that the engine is running rich. However, my dad and I pulled the spark plugs from Bank 2 (side facing the radiator?) and they were all clean. We haven't checked Bank 1 yet, because it doesn't seem related. Is it worth the effort? I even pulled the MAF sensor and cleaned it with isopropyl alcohol just in case.

The car stalling downhill while braking seems to suggest a vacuum leak, but I tried the tube-to-the-ear-with-the-engine-on method and couldn't pinpoint anything. I haven't tried smoking it yet, but if it does turn out to be a vacuum leak, I'll bring it in to a shop with a smoker. Something worth noting: while searching for the vacuum leak, I removed the plastic engine cover and noticed that the hose coming out of the PCV valve was collapsing under the suction. After removing it, there was a yellow-ish milkshake-like substance inside the hose and the valve, which I looked like oil and water mixing. I don't think I have a bad head gasket because I checked my oil and there wasn't any water in there, and I'm not leaking coolant out of the exhaust. The PCV valve surprisingly wasn't clogged because it was rattling after I pulled it out, so I stiffened the hose coming out of it by pushing another hose through the inside and that fixed the collapsing. I'm hoping the oil and water together was just condensation on the inside of the hose.

Also, from what I've gathered, C1175 deals with the driver's side rear ABS sensor being corroded? How could I locate and fix that? Does it have anything to do with why I have a "DSC SYSTEM FAULT" warning?

And I have no clue what P1638 means...

Basically:

1. Should I bother with checking the condition of the Bank 1 plugs, even though they weren't mentioned at all?
2. What's going on with the rear O2 sensor and how do I locate/fix it?
3. Am I running rich?
4. Is my MAF sensor related to P0174 at all?
5. Does it sound like I have a vacuum leak?
6. Why is my PCV hose collapsing?
7. Do I have a bad PCV valve?
8. Is there a bigger issue like a head gasket?
9. How do I change the sensor that causes P1175 (if that's the issue) and is it why I have a "DSC SYSTEM FAULT" message on the odometer?

Sorry if there are too many questions; I just want this car to purr like it was meant to. Thanks in advance!

 

Codes are in JTIS, free download

 

Nathan - welcome.
I'll try to provide some help.
1. - I'd concentrate on other issues for now.
2. - It sounds like it is shorting out somewhere. Check wiring for breaks.
3. - Yes, probably - Checking your long term and short term fuel trim settings will show. This will destroy your mileage.

4. - A vacuum leak will make your maf readings inaccurate.
5. - Yes. link to common leaks jaghelp.com: Jaguar X-type common vacuum leaks. P0171 and P0174
6. - It sounds like you have the old style breather hose - it should be replaced with the new style.
7. - You might but probably not.
8. - Very doubtful.
9. - There are several reasons for a sensor problem. Dirty sensor, bad connection, bad wire, bad reluctor ring for a few. These sensors are used by the DSC module to determine wheel speed.

There's a ton of information in the FAQ sticky at the top of this forum. An advance search of your error codes individually in the X-Type forum will show you what has been discussed previously.

Good luck. It doesn't sound like you have any major problems.

 

Thanks for the help! I'm gonna take a look at the vehicle this weekend to try some of this stuff!