Hi All,
I'm a proud owner of a 2005 x-type 2.5l petrol, that has just failed its MOT due to Emissions - failed sensor.
The sensor before was replaced at the last MOT but lasted 2 months before failed and light shows on dash.
I've rightly been advised not to just replace another sensor but root out the cause and resolve.
My man is not a Jaguar specialist and has advised me to seek one out.

I have 2 questions please;
1. Do I replace the exhaust and/or a new sensor to get me through the MOT?
2. Being a Ford ST (sorry I hate it too) does this have to go to a Jaguar specialist to be fixed?

He is calling me back with some pricing on other work to her and I will ask if the Lambda reading is high or low to try to steer towards the cause.
Any idea's please?

 

MHammond, what error code are you getting? That is going to help us out a lot. I am assuming you have an O2 sensor that is failing. The first thing that I would try is what some refer to as an Italian tune up. In short, what you want to find is a long uphill and if possible, put some people in the back seat. What you are going to do is to get going as slow as you can and then do a long, hard acceleration up that hill. What you are trying to do is to put a large load on the engine which will warm up the exhaust and this should get the cats nice and hot. This will help burn out any carbon that you can in there. I would then clear the codes and see if the same code comes back. May want to do a few long, hard pulls like this to ensure you burn out what you can before resetting the car. That may do the trick.

The next thing I would give a try is a can of Seafoam. What you are going to do is to pull the line from the brake booster (comes off the top of the intake) and then stick a rubber tube into that hole with the other end in a can of seafoam. You will want to pinch the tube closed. With the engine up at temp, you are going to unclamp the tube and suck down about 1/3 of the can (will need to step on the gas to keep the engine running) and then let the engine die (sucking down a little more of the can (want to get to about 1/2 a can). Let the car sit for 10 minutes or so. With the tube pinched off again, start the car and get it up to idle, then undo the clamp and suck down the rest of the bottle of Seafoam (fighting to keep the engine running). Once the Seafoam is gone, pinch hte tube shut, get the engine to idle, remove the tubing, reinstall the original tube and take the car out for a drive. The car may smoke like you won't believe. This is normal. Take the car out for a drive and do a series of hard pulls and high RPM runs (use the J-gate, downshift, keep the engine RPMs in the 3-4,000 range). This will burn out the rest of the Seafoam. This will take about 5 minutes worth of driving to do this. See what you have at that point.

Now, this is all assuming you don't have a hard fault in the car. This is where the code is going to tell me a lot. It is possible that you may have a bad power lead to the O2 sensor, which will cause it to read erroneously and give you trouble. You may find that the wiring is getting too close to an exhaust pipe and is damaging the wiring. There are tons of possibilities based on what you have said.

 

Are you sure it's the same sensor as before? There are four altogether, two for each bank of cylinders and failure of any one of them will cause an MoT fail. Any generic scanner will tell you which one is the dud one

If you have to get a new one, your surest way of long term success is to buy a genuine Jaguar one. Cheap copies have a poor record of reliability.

 

Hi MHammond!

It's important to know the DTCs in detail as Thermo noted.

More often the root cause is sitting in chain before the component which causes a DTC. (The component often only noticed the defect.)

In front of the catalyst of each bank there is each a controlling sensor (this motor: a wideband sensor, more costly).
After the catalyst there is each a monitoring sensor (more simple type, "jump sensor" [I don't know the exact English name]), this sensor is only to check if the catalyst works sufficient.
The values of all of them can cause different DTCs.

Often the real root cause (on several makes and models) is a vacuum leak (a hose or hose connection), or a defective air mass sensor (exact English word?).

You should pay attention to the short and long term fuel trims. It's values can show whether there is a vacuum leak (or similar).

In one case I'd to change one of the wideband sensors at a X-Type. (I'd to check the motor code, it was long time ago.)
I didn't chose Jaguar original spare part (really high price), instead a Delco (or similar) with the right plug prefabricated.
(Of course - it's an adapted Ford [origin Mazda/Suzuki development] motor!)

A more universal O2 sensor without a plug even would be more cheap. But you have to solder the old plug.
And this could be a problem: Some sensors get it's reference air through the core of the wires (really!), near by the plug, so with wrong soldering you would break this way / techniqe.
I don't know if wideband sensors use external reference air at all, some kind of O2 sensors uses internal caged reference air.

If you are intrested, I would look for the motor and exact type of O2 sensor.


Cheers, catfondler

 

I also have a 2003 X-Type 2.5 . 107,000k I have with in the last yr changed all the upstream and downstream sensors (bosch), denso fuel injectors,bosch spark plugs, breather hose, MAF sensor, ignition coils, radiator, coolant hose upper, lower and reservoir, throttle bottle cleaned, oil changes, and coolant flush, new belts and tensioners, water pump, upper and lower manifold gaskets, thermostat, filters, cabin and engine among some of the many points I had done. I had smoke test done and fuel cap changed. I have lean codes and smell of gas when i start the car. Any ideas? Car drives well.

 

one of the o2 sensors is not reading although new.

 

Xerxes777, just because you have new parts in the car, do not assume that they are good. From what you are describing, the O2 sensor that is failed is either bad or, the wiring between the ECU and that plug for the O2 sensor has been damaged. This is where a little bit of electrical checks with a multimeter will tell you which is bad. Do you have the schematics for the car? If not, look in the stickies above and you will find the diagrams. Just note, you have the 2002-3 diagrams and then you have the late 2004+ diagrams. You need the 2002-3 diagrams.

As for the smell of gas when you start the car, yes, you will get this. The motor needs to run a little rich when it is cold to keep it running. But, once the temp gauge gets up to temp, you should not smell fuel any more. If you do, then we have an issue.

You mention new spark plugs. I see you bought Bosch plugs. Did you try and get the Bosch +2's or the +4's (or any other multispark) plug? If so, that is more than likely your issue. The X-Type hates (with a passion) any sort of fancy plug. It wants a straight platinum plug with the proper gap (0.054" +/- 0.003"). I have helped a lot of guys that had similar issues and we traced it back to a plug that the car simply did not like. It is picky. What can I say.

The last thing I would say to initially check is your VVT seals. WIth the mileage on your car, these may be getting old and starting to leak. that will cause a lean condition. Just for clarity, are you getting both P0171 and P0174 codes, or just one of them?