Hey guys! Thank you for having me here! So i recently just bought an 03 Jaguar X-Type 2.5L and it has its engine light on, ABS light on, DSC failure on and cruise control unavailable. It misfires a little at around 3000rpm and has a rough idle; with that, sometimes in the morning when I start it the rpm goes from 600rpms down to 0 until the car shuts off and the battery and the oil light comes on- to add on to that, it’s averaging 12mpg. I got it checked with the code scanner yesterday and it read 4 codes which are P0171, P0174, C1145, and C1175. I’m still currently working on the right rear shock absorber and left rear brakes and that’s probably why the last two codes showed up? Still not sure. For the first 2, I was told that it might be a vacuum leak but how do I start to find where the leak is? I’m new to this Jaguar community and cars in general, any help is greatly appreciated. Thank you!!

 

 

Vaucel, like your thinking, the P0171 and P0174 codes are for low vacuum in the intake. Because you have both, I would start with checking your PCV hose. If you remove the cover off the top of the engine, just to the left of the throttlebody, you should see a hose about the size of your thumb running from the front valve cover to the intake manifold. remove one end of the tube and pull it up and feel the underside of the tube. Do you find that the tube is split (lengthwise)? If yes, this is your problem. This will be especially true if this tube is smooth. This tube has been re-designed and has ribbing added to it. If this is not your issue, then I would next look at the two IMT valves (black disks on the left side of the intake facing the one front tire). These have an O-ring in the joint and is a known source for vacuum leaks. After that, there is a line that run from the top of the intake, over to the brake booster. In the middle of this line is a small "football" (it is a check valve). The plastic this is made of tends to dry out over time and if you rub the "football" with your thumb and you get dust off of it, you will need to replace it. You may also find that this will have a crack in the plastic. In some cases, you may even find the brakes are not working really well either.

If these 3 things do not fix your issue, then you will most likely need to a "smoke check" of the engine. This is where I would recommend getting yourself a nice cigar and smoking it (or finding a friend that smokes). With the engine cold and the A/C-defrost turned off, start the engine and then gently blow the cigar smoke into the engine bay. What you are looking for is the smoke to be gently rolling through the engine bay and then suddenly make a sharp turn towards the engine. Where the smoke runs to is where your vacuum leak is. Odds are, you will find that if you have reached this point, you are going to be looking at the intake manifold gaskets (2 sets, referred to as the upper and lower gaskets, the uppers you will see if you lift off the intake to change the plugs, the lowers are right on the cylinder heads themselves).. If you need help, let us know. Vacuum leaks are a common problem with the X-Type.

As for the C1145 and C1175 codes, those are for the wheel speed sensors. C1145 is for the right front wheel and C1175 is for the left rear wheel. The left rear wheel speed sensor is most likely a bad reluctance ring. If you remove the wheel speed sensor and look down in the hole (where the sensor was), you can shine a flashlight down there and look for a metal ring in there. It should be tight against the shaft. If you see any gap, the ring has rusted and broken. You will most likely need to replace the half shaft for that wheel (common issue). As for the right front wheel, start with checking the wiring to make sure it is not damaged. Next, has the wheel bearing been replaced recently? I only ask this as the wheel bearing is what the sensor uses to sense the wheel speed and we have found that not all shops know that there is an inside and outside to this bearing and if it gets installed backwards, will cause the wheel speed sensor to not be able to sense the wheel. At this point, if you are suspecting the sensor itself, you can either try swapping the sensors side to side to see if the problem moves or you can simply get a new sensor and install that. If you are still having issues, then let us know and we can help you out from there.

 

 

 

 

Vaucel, if the throttlebody was causing the codes, you would be getting different codes. odds are, if the previous owner was playing with things, you are looking at the upper seals. possible the lower ones will need to be replaced. This is where the smoke test will tell you a lot. The seals are not that expensive ($20 for the uppers, $25 for the lowers, can be gotten at any local auto parts store, simply tell them that you have an 03 Lincoln LS with the 3.0L and they will get you the correct parts, if you tell them the jag, they can only find the uppers, not the lowers, the Lincoln 3.0L engine shares a lot of parts with your engine, but not all). The repair work would take you about 3-4 hours to get down to the lower intake seals. if you need a step by step, just look around here. There are lots of write ups with pictures to show you how to get to where you need to be. Not a hard job. if you are in the DC area, I would tell you to come over and we can crank it out in an afternoon easy.

 

Vaucel: In addition to Thermo's guidance, try cleaning the Mass Air Flow Sensor (MAF). When dirty, it measures less air than the engine actually 'breaths', so the ECM adds less fuel than the engine needs, causing a lean condition, similar to a vacuum leak. It's easy to remove and clean. Use MAF or electronics cleaner, not carburetor or brake cleaner (which can leave a residue).

These post shows where the MAF located on our X-Types and how to clean it:

Jaguar X Type Information:- Petrol Engine MAF Sensor

Jaguar X Type Information:- Petrol Engine MAF Sensor Repair

https://www.jaguarforums.com/forum/s...-sensor-34863/