Hi all, I'm currently looking to buy a Jaguar X type vehicle. I have found one located fairly close to me, the only issue is the woman that currently owns the vehicle says the vehicle is in limp mode and the TCM module needs to be replaced. When I asked her how she came about this information she said the car wasn't accelerating correctly (very slow on the start) and it threw a dashboard warning. When she took it into the shop the guy pulled the code (she didn't know what the code was) and told her she needed to replace the TCM. He told her she could drive the car like it was, just don't pull out in front of anyone. She says the car is basically stuck in low gear and that it will eventually get up to speed, just takes a while to get there. Other than this the car appears to be in fantastic condition. Does this sound like a worth the risk or avoid like the plague situation? I didn't think "limp mode" worked like this.

 

Hard to say based on your brief description. What would be the most helpful is if you could get the code and post here. IF it would be just a TCM you could replace that fairly easily and not too expensive if you would get a used one. If you really like the car, get the code read and go from there.

What is the asking price or other details about the car?

 

The exterior and interior of the car appear to be immaculate from the pictures she sent. The tires are 6 months old and the car is clocking in at 118,000 miles. She had the timing chain replaced at 100,000 miles. It wasn't giving her any issues but her father wanted it done and funded it. She has the receipts for the work. Her asking price is $1900. According to her there were no other codes. I'm am probably going to drive over and look at it this weekend. Sometimes pictures can be deceptive. I will try to get the car to an Autozone and get the codes read.

 

Replaced the timing CHAIN? That girl's father must be confusing that type of replacement with a timing BELT, which do need to change. The chains don't need to be changed. That really seems to be money wasted unless there was a specific reason. Am surprised that whoever did the work didn't tell him it wasn't necessary, or maybe he did. Oh well.To each his own.

Hope the car is as good as it might appear and if there is a code and it is something that can be fixed relatively easy and that is the only issue, you might be able to use that to reduce the price and get a nice car cheap. But, as you said, pictures can be deceiving.

 

Ok, so I drove over to check out the car yesterday. The body was in pretty descent condition, no dings or dents, the clear coat was starting to let go in one small place just the rear of the sunroof in the center. The back "spoiler" such as it is would need to be replaced or removed (not sure if it is removable or if this would leave holes). The interior was in very good condition, even has the original jaguar floor mats in it.


Now for the bad...apparently her mechanic told her incorrectly or she misheard on the whole "it was only showing one code" thing. We went to Discount Auto first, their code scanner wouldn't even communicate with the vehicle. So we drove the car over to an Auto Zone. Their's connected right up and pulled the following codes...


P0037, P0057, P0174, P1637 ( it listed this one twice for some reason) and then a code P1000 which said something about diagnostics not complete. She is going to try and take the car back to the guy that originally told her she needed to replace the TCM and have him pull the codes again and see if it is different.


Can we determine anything from the codes we were able to pull at Auto Zone? Thanks in advance for any help or advice.

 

THta is an interesting mix of codes. I have attached a PDF showing the Jaguar codes.

The P0032 and P0037 show a problem with both the upstream and downstream O2 sensors on Bank 1. The P0174 is a lean condition on Bank 2 and is something you would typically see with a vacuum leak, but could be triggered by O2 issues, but the codes associated with the O2 sensors are for Bank 1.

The P1637 is the wild card as it has references to CAN circuit faults.

P1000 just means the system check is not complete. That is probably just because the fault that there is intermittent. Once all the parameters are met you would see P1111.

My guess is that this would be something that wouldn't be too bad to address, but it is impossible to say. Maybe someone else could chime in with more experience than I. If this was a car you owned and could try a few things one after another and report back here would be one thing. But when it is a car you are looking to buy and it could be a wiring or ground issue or something else that is a little scary. I guess it all depends on how good you are at working on cars. Could be something quick, easy and cheap or could be a little more involved.

 

One other thing I should have mentioned...when the car was idling, it didn't idle very well at all and I could definitely smell gas. She said her mechanic told her this was all due to the TCM module, fix that and everything else would be golden. I thought the TCM just controlled the transmission or is that vastly over simplifying what it does?

 

Scott, from the sounds of things, tell her that you will give her $1700 for the car as is. She will more than likely take it with the number of issues. I would then undo the plug for the downstream O2 sensors and do a resistance check between pins 1 and 2 to the sensor. You should get something under 5 ohm. If you are getting over 10 ohms, then the O2 sensor is bad and it needs to be replaced. Not a tough job, but does require getting under the car to get at the downstream sensors.

The P0174 code is more than likely a vacuum leak. Odds are, you are looking at either the PCV hose (is it a smooth hose or a ribbed hose, if it is smooth, odds are you will find a split on the underside of the hose) or the IMT valves ($5 o-rings and a few minutes of your time).

Now, for the P1637 code. This is the one that can be a bit tricky. This is where having a mechanic look at the car and put their computer on the CAN bus can be very informative. From the sounds of things, you either have a bad TCM or a bad ECU. Either will cause what you are seeing. It is possible that there is a wiring issue between the two, but unless someone has been monkeying with the car (which in this case sounds like the person always took the car to a mechanic), the odds of a wiring issue are pretty small. The $100 you pay a mechanic to connect up their computer to see which computer is missing/not sending out information will be money well spent to prevent replacing parts just because. Like was mentioned, replacing the TCM is pretty easy and straight forward and should be able to be done with no reprogramming needed. The ECU, well, that is a different story. That will definitely need reprogramming, so, you are looking at the price of a good ECM plus another $100-150 for the programming. Unfortunately, odds are, you are looking at having to suck up the cost of a dealership run.

The poor idle is more than likely due to the P0037 and P0057 codes and the car having a hard time finding a good fuel concentration to put in.

Hopefully this gives you an idea of what you may or may not be facing.

 

Would it be safe to drive this car the 120 or so miles back to my house or would I be better off trailoring it?


Edit....


Another question, is there a better code reader for these type cars that I could buy that would give me a better idea of what is going on than the ones the parts stores have, or would that be prohibitively expensive?

 

Scott, I would not recommend it. A rule of thumb is if the check engine light is flashing when the engine is running, then you are causing damage to some part of the car. But, with the smell of gas coming from the exhaust, this is telling me that the cat is starting to fill up with carbon which is going to lead to it getting clogged. Then you are looking at a fairly costly repair then to replace the catalytic converters.

As for a code reader, if you have an android based phone, look up "elm 327". This is a cheap code reader that you can link with your phone to (via bluetooth). You can get the cheaper version that is compatible with the Jaguar line. This will set you back about $20. There is a more expensive version for the 2004+ cars due to slight changes in how the CAN bus is used. But,it will work with your car too. The newer version is $40. The software you need to download is a free app called "Torque". If you pay $5, you can unlock the program to access the dyno feature and some other high end stuff.