I posted this under the tech section of the forum but since I got no replies I'm guessing I was supposed to post here. I'm new to the forums and I recently bought a 2003 X Type. I really like the car and I am enjoying it, but I have my first concern. Yesterday the check engine light came on and I noticed the car was shuddering just a bit while idle and sometimes it feels like it is going to stall, but never does. I took it to Autozone and they were able to get this error code indicating some type of electrical problem. They advised a tune up would likely solve the problem. Does anyone have more specifics on what this problem could be and perhaps how much it will cost to fix? Thanks.

 

I could tell you but then we have to kill you.

This is going to sound dumb, but P1638 has to maybe do with a problem with CAN, Controller Area Network. Do a search for JTIS here and get a copy. Sometimes codes will jump up and be caused by something else. Sometimes you can get a code from one of the code readers plugging in. If it really is the P1638 problem you will need to see the JTIS and track it down. Jaguar Technical Information Systems. You will need issue 21

 

Go to this thread: https://www.jaguarforums.com/forum/j...-1638-a-26691/

Go down until you find a post by "MOTORCARMAN." He has included a PDF file about a service bulletin dealing with this. Some code readers aren't set up to work with the CAN system.

if things don't clear up, you can try a "HARD RESET". Key off. Disconnect the negative battery cable from the negative battery post. Turn the key to the on position. Nothing should be working due to no power. Go back and take the nagative cable and touch its clamp to the positive clamp on the positive post. Hold it there and this will put everything back to default. Turn the key off and reconnect the negative cable to the battery. It will take some idle time and drive time to let the system learn.