Couple of things to point out...

1. There is no such thing as an OCTANE SENSOR per say..There is however, a sensor called the Pre-detonation or KNOCK sensor which feeds inputs to the ECM to retard ignition timing due to pre-ignition as a result of LOW Octane fuel..It's a learning process and takes several tanks of gas (of the SAME OCTANE) for the ECM to trim out everything for optimal performance with that type of fuel...Lower Octane fuel (below that of the minimum requirements) makes the ECM retard the timing enough to affect the performance...your call on what you use, but eventually this leads to possible carbon build up in the cylinder heads.


2. The type of fuel regardless, will not affect the TB (Throttle Body). Fuel does not flow through the TB, only air does.

 

Well... this was day two with the new throttle body and guess what? It went back into limp home mode after rolling 60 miles on it. I am so fed up... $1000 spent in the last week alone and I still can't rely on this car. I'm making a trip back to the dealership tomorrow to see what they will do. I'm guessing they won't do a thing since there's no warranty and I've had it for two months. They gotta take it as a trade in or something?

The only thing I'm noticing is that it seems to rain every time I have this problem. Either that or I just wash it. I've heard of other people having trouble with water getting into the TCM. Is this a possibility?

 

Do a search in this forum for my name and it will give you the complete story but a Coles Notes version is, 04, 3.0 X that I got used with about 50K miles on it, day 1 CEL came on, no biggy needed a new fuel cap, day 3 gearbox fault and limp mode (pouring rain). Took it back to the non Jag dealership and they sent it to Jag. Scan was a TCM fault but when it was cleared they couldn't get it to return. I drove for a week and then...pouring rain...it came back. My dealer said take it straight to Jag, the TCM was shorted from water, put the car in a spray booth for a water test and the water was coming in at the bottom of the windshield, leaking down the wires and frying the TCM. So new TCM, and new lower valance piece (the plastic thing the wipers mount through) and so far so good. (knocking solidly on wood). So in answer to your question that's exactly what happens. From what I gather the TCM can be the root of all evil with the X-Type. Ive heard people get 200K miles when serviced properly but as in my case, the windshield was replaced and that valance piece installed incorrectly and it led to 2 months of woes. Don't give up, usually the simplest reason is the reason. Rain.

 

Thanks for the info. I passed that on to the Jaguar dealership but they still have no news for me. This is day 5 now and they have yet to diagnose the problem. I'm now spending even more money renting a car while they look at it. Sadly, I think they are clueless and unqualified!

 

So it looks like I will finally have resolution after the Jag dealership has had my car for two weeks. They finally got the car to go into limp home mode on Monday. The diagnosis is a faulty ECM. The best part is it will be covered under the 8/80 emissions warranty. I pick the car up tomorrow afternoon.

 

I didn't read through the whole thread but the OP sounds like his throttle position sensor has gone bad... If you take it to the Jag dealer they'll tell you to replace the entire throttle body because "Jaguar doesnt seller just the sensor alone." $1800 for parts and labor. Same exact thing happened to me in my car.

 

Interesting Kevin. I just got my X-Type back from the dealership yesterday. Although the ECM was covered under maintenance, I still paid $372 for diagnostic fees. The car drove fine yesterday and all day today. Tonight, my wife was coming home late from having dinner with a girlfriend. She called me at 10:30p stuck in the parking lot in limp home mode. Guess what? It is raining cats and dogs tonight. When I took the car in to the dealership 3 weeks ago, I asked them to test for water leaks. I believe they blew me off and just said they saw no signs of water damage to the TCM.

After reading your post, I went outside with a flashlight and there is a huge gap between my windshield and the plastic trim. I took a look at my other cars (a Jeep Grand Cherokee and a VW). Both of those have a water tight seals between the windshield and trim.

The question is, if I seal that trim piece myself with a water tight silicon caulk, will that eliminate my problems or is there permanent damage to the wiring harness or other components? I have nothing to lose at this point so I'm going to try and seal it myself. The car seems to drive fine I encounter water.

I've spent $1,500 in the last month at Matheny Jaguar in Jacksonville, FL and have received no results whatsoever. They simply do not return phone calls and are in no hurry to give any updates at all. I had to call the service manager directly every day for the last week to find out what was up with my vehicle. I cannot afford another 3 weeks for them to continue their diagnosis at my huge expense. HELP!

 

Sorry for my delay in posting any progress/follow up. I've had pretty limited internet access.

To answer a previous posters question regarding fuel octane, I've always used premium fuel....91 to 93 octane in my area.

The more severe of my symptoms was in fact due to a bad throttle position sensor. The bad TPS was causing severe limp mode and an alternating transmission/engine warning as well as the P0121 code.

Once I relplaced the TPS and cleared all codes with an OBDII my car acted normally for about one day.

Now I'm back to the same CEL and Cruise Not Available error. I've checked codes three times since the CEL came back on and received the following errors:

1ST read: P0171, P0174
2ND read: P0171, P0174, and P0420
3RD read: P0171, P0174

P0420 seems to be an intermittent error code.

I've checked pretty thoroughly for any vacuum leaks and have yet to find any. I've replaced the PCV hose, IMT o-rings, as well as the brake booster hose.

I do have a K&N air filter which I've checked and I've also cleaned the MAF sensor thoroughly.

I'm going to check the "seal" between the windshield and the plastic trim. I'm also curious if there would be any damages if that were the root cause of the problem.

Any other input is greatly appreciated.

Thanks!!

 

The gap between screen and valance is usually the result of bad fitting after a front screen change. There's a thin lip running the length of the underside of the valance and it's supposed to slot into the hard plastic strip attached to the base of the screen, but it's not easy to get into place. On my car, half of it had broken off and there's a large gap between valance and screen just above the cabin air filter.

I haven't had problems with the engine, but whenever it rained or I used the screen washers the inside of the car misted up. I fixed it by removing the valance and fitting some flexible plastic to the top of the filter holder - enough to deflect any water running down the screen and prevent it from getting inside the filter holder and hence into the car.

 

I'm still not sure where the water is coming in on mine. I don't see any signs of water inside after it rains (no misting, no drips and no damp floor mats). I did seal the trim by the windshield and a piece of plastic trim that was coming up on the driver's side rail that diverts rain from the roof. I just taped everything off with painter's tape and then used a tube of black rubber windshield sealant that I picked up from the auto parts store. I haven't had any trouble with it in a week but I've been keeping it in my garage and haven't driven it in the rain. It doesn't appear to have any permanent electrical damage yet. Wow... I replaced the ECM and the Throttle Body. I guess I can put my old TB on eBay.

 

Thanks to another forum member I was able to resolve my issue. I believe that half of my problem was caused by a bad TPS and the other half was a vacuum leak.

Here is the fellow members correspondence with me via email:


I haven't been on the forum in a couple weeks, just too busy. You're getting the cruise unavailable due to the lean condition. The ECM has an engine preservation program that will disable the cruise to protect the engine from mechanical damage should it be so lean as to burn a piston at high speed. If you don't have any transmission codes I'm not sure it will be worth checking the TCM for water. You are probably getting a bucking at about 2800 rpm when you accelerate hard due to the ECM limiting high rpm operation and it has nothing to do with the trans. If you do pull it out no programming will be required when you put it back in unless you replace it with a new one. You really need to fix the lean fault or that p0420 will become permanent. 420 is bank 1 which is the bank nearest the firewall and it indicates the catalytic converter isn't working at best efficiency. Nothing else is very common but there are other areas that can leak vacuum. There is one large vacuum line that attaches to the back of the upper intake on the drivers side and it is possible it is cracked, off or oil soaked and leaking. The map sensor on top of the intake has a small o-ring that could be missing if someone had it off for some reason. There is an o-ring on the dipstick that seals it to the tube that likes to come off. I've never seen those last 2 cause codes on an x-type but they do cause lean codes on the v8s. If someone had the upper intake off to change coils or spark plugs they could have displaced one of the sealing o-rings at the fuel rail but those usually leak bad enough to hear. You can try this test for leaking intake o-rings. With the engine running at idle spray some throttle body cleaner down around where the intake meets the fuel rail and listen for an increase in idle speed, an increase would mean a leak that the cleaner was sucked in through. Lastly there is a plate bolted to the top of the engine block under the fuel rail that is sealed with a rubber gasket that could leak as well. It can't be seen with the intake and fuel rail in place but the throttle body cleaner test should help find it. It's on the drivers side of the block about 2 inches in from the bellhousing where the trans is bolted on. Do be careful with the throttle body cleaner. If it gets sprayed or drips on the exhaust it could cause a fire and I'm sure you don't want that. Let me know what you find and don't hesitate to e-mail with any other qustions."

My issue was with the section in red.

This is a picture of the motor with the intake manifold removed. You can see the fuel rail and upper intake gaskets.



Here is a picture of the motor with the fuel rail removed. You can see the coolant line in the middle and direclty beneath it is the "block" that was referenced above. I couldn't remove the plate all the way. I actually removed the coolant pipe (black) but left the flange that is bolted to the block still attached because I couldn't remove that part. I was able to remove one bolt on the plate and loosen the other (circled in blue) so that I could place some silicone sealant between the plate and the block. I did not obtain a factory gasket, just used the silicone. I let it set, put everything back together, and my issue was resolved. It was also a great opportunity for me to change the plugs since I had the manifold off. All in all the job sounds a bit worse than it actually was.




Here is a picture of the back of the intake manifold where there is commonly a leak found:





Good luck finding a resolution. I hope this can help you.

 

Well, the local Jaguar shop never resolved the issues with my '04 X-Type. I originally posted to this thread a year ago but I still get email updates to this forum so I thought I'd take a minute and give you the status of my troubles.

I spent a little over $2k and was without my car for a total of 8 weeks while Matheny Jaguar played with it. Things that were replaced were the ECM, Throttle Body/TPS, and EMT O-Rings. The ECM was done under the 8/80 emmissions warranty. None of these things fixed the problem. I grew so frustrated with wasting money and interacting with the dealership that I gave up. They actually had cars that were doing the same exact thing, in their garage on blocks for over three months. Total incompetance.

Anyway, my wife discovered that the car would go into limp home mode only if the RPMs dropped below 700 at idle. My fix... I've been driving it for the last year with one foot on the gas and the other on the brake when I come to a stop. It's like second nature now. I just keep the RPMs over 700 and I have had zero issues for a year now. Two weeks ago I decided to drive it normally just to see how long it would go... by the end of the day it was back to transmission/engine fault and limp home mode. Haha... I shut the car off for 5 minutes and started it back up... making sure to keep my foot on the gas and RPMs over 700 - no more problems. I'm resigned to the fact that I'll be driving it like this forever... but, it beats stressing out over dealing with the Jaguar mechanics and managers.

 

I am experiencing the same problem.

No idea where to begin... but I know I need to begin. I cant sell the car if its broken! Can't drive it if its unreliable! Nor am I going to take it to the Jag dealer just to have no resolution thousands of dollars later.

:i con_shrug:

 

I have owned a few cars (6) and I have put 120K on them. I have never used high octane. Minnesota has 10% alcohol from Dec. to May. My present Jag a X-type 2.0 has 122K runs fine. Is it possible that the fuel related problems I"m reading about is alcohol related or contaminated. I only use stations that have filters on the pumps and inspection tags dates of no more than 9 mos. old. I know the newer cars should accept the new gas mixture but if your area isn't conforming to the standards,eg. higher alcohol mix, not changing/having filters. The octane rating won't matter because the computer will compensate for (pinging) problem. Also high volume gas stations won't be subject to condensation in the tanks which alcohol helps alleviate but contributes to other problems. Some people dump bottles of alcohol and cleaner in there tanks that does NOTHING if you have good clean fuel except to dry out fuel systems and cause problems, even the manual says USE NO ADDITIVES. My last car went 230K and never had a fuel pump or filter change.Just thought I'd throw this out there as a FUEL FOR THOUGHT.

 

I am having the same experience from Matheny with an 04 XJ8. 50 days plus in and out of dealer. Horrible dealer service has communication problems, confusion, replaced parts without fully testing the car after I told them it has a short. Waited 30 days for a module, then the car still doesn't run. Replaced fuel relay switch. $1800 at dealer plus rental cars and still the same problems pop up within a day of driving it home. Took the car back and they want $800 more to diagnose the short that should have been detected in the first place. Car sat for 2 weeks while Jag US told us dealer would test the car as the same problem is recurring. Picked it up 2 weeks later and told conflicting stories at dealership. Just disgusted with Matheny. A hyundai dealership could give better service than these clowns.
Do you have anyone you can recommend in Jax to work on Jags other than the dealer? I am certain I have a short somewhere and Jag dealer service advisor told me to drive it until they get more codes. I took it back with at least 5 fault messages, but I guess they think the car will give a code that says I have a short??? Not likely. Thanks for any help. Ready to trade for a MB after only 6 months of ownership.

 

Hey JaxHusky. Sorry to hear about your trouble. That sounds about right unfortunately. I wish there was another Jaguar/Land Rover dealer near Jacksonville. I have a friend who has had the same luck with her Range Rover purchased from Matheny. During my last visit to the dealership, they had several Jags that were up on lifts and had been in the shop for 3 months (that is according to one of their Service Managers). It's ridiculous. With any other car I've owned, when there is a problem, I take it to the dealer, they diagnose and fix the issue and I'm driving it again in just a day or two. I'm convinced these people have no clue what they're doing OR there are a thousand possible causes for the one error code they read. Either way, they're supposed to be the experts!

I did make a call to Autobahn motors in Jacksonville. They gave me the number to an ex-Matheny mechanic who does all of their Jaguar work. I called him and his rates were reasonable and he seemed to know what he was talking about. I ended up finding my own cure so I never actually used him. I don't know what I did with his number. The only advice I have is to maybe call Autobahn and ask them for the number to their Jag mechanic. Sorry I couldn't be more help!

 

I was just rereading your post, and the part I waited a month for as it was backordered is an ECM. Paid $900 to dealer for the part, but it looks like it should have been a warranty item under 8/80000 emissions control. I will call autobahn today and hope they can direct me to the right person to get my car back to normal. My husband followed me from the dealership and immediately turned into the nearest Mercedes dealer, Brumos, to car shop because he is so disgusted with Matheny. Thanks again for the advice and your post info.

 

Hi all, I was wondering if any of you can help me, I got to codes with my check engine scan P0420 & P0171, can someone help me?