Hi everyone,

2002 Xtype 3.0 automatic. My battery went bad the other day as it had been marginal since i purchased the car (never above 12.5 volts). Well finally the starter wouldn't turn over so I put a new battery in. I also put a new negative battery clamp on because mine was shot. Since that things have not been going well. I first noticed that the back button on the sunroof stopped working. Now only the front part of the button does anything. Today I went to move the car and noticed when I pulled the key out of the ignition that the nav screen stayed on. So basically the radio wont turn off, and none of the buttons on the volume knob panel by the cassette do anything on the screen when touched. They still work, but don't show any corresponding action on the screen. Also, my positive battery cable is getting so hot that I burned myself on it. Seems to stay cool when the car is off, but heats up very fast when its running. I've tried disconnecting the battery, erasing memory from modules by running a jumper from positive clamp to negative terminal. Also, I have good continuity on my grounds to the body and engine without any resistance. I did notice that my resistance from the positive battery clamp to the starter has high resitance when the car is running, and it cuts in and out like 140 ohms then drops off then goes back to 140. I'm thinking I should start with new battery cables and then go from there. The car also leaks when parked facing downhill and it rains. It rained last night and the trunk had a lot of water in it as well as my passenger foot well. I'm sure that has something to do with it also. Another thing to mention is that when i touch my positive terminal to my clamp there is only a small spark nothing major as if there is a heavy drain. Also, m alternator is putting out 14.5.

Any help or suggestions is greatly appreciated!

Thanks,

Darren

 

Replacing the cables should solve your electrical problem. The positive cable should not be heating up. It may just be a connector to wire joint but I'd replace them to be sure. To solve your leak - park it up hill.

 

I'm going to pull the battery cables off and check resistance off the vehicle and do a inspection of them. Also, perhaps the starter is shorted out? I was having issues before I put the new battery in where it wouldn't start and when I hit the starter it would start. I summed it up to just being due to a weak battery since it has been working fine since replacement. In regards to the leak... I usually park facing uphill and everything is fine, but I didnt realize it was supposed to rain and screwed up. I wasn't having electrical issues when I was parking it in the garage, but now my recently purchased 77 XJS is in there.

Thanks!

Darren

 

Replace the positive battery cable. Unless you have a very sensitive resistance meter (ie, one that can measure down to say 0.00 ohms), seeing a higher than normal resistance in a battery cable is going to be hard to do. If you are seeing resistance on a battery cable, then it is well beyond being re-used.

It has been shown that if the car's voltage starts to drop (ie, from the heating up battery cable), this will cause really funny things to happen with the car's electronics.

 

I really do appreciate all of the suggestions. So the car has sat for a couple of days with the battery disconnected. I hooked the battery up to it yesterday and everything was working normally. I left the battery connected and went to work. When I returned the screen was on again. Does anyone have the correct wiring diagram for the nav unit. I can get the screen to go blank by pulling a fuse, but the clock display below remains on. I figure if I can figure out what feeds the radio I can track down whatever is causing the issue. Also, wanted to mention that the battery cable getting hot is also intermittent. Yesterday I ran the car when I thought is was fixed and the cable was cool to the touch, but today the radio wont go off and the cable is hot again. I could've swore I had the repair manual downloaded somewhere, but I don't and I cannot get the one in the sticky to install onto my computer. My guess is also the positive battery cable, but I want to be sure before I spend $100 on a 1 foot piece of wire. Thanks again! I will keep everyone updated.

 

jag87, send me an PM wiht your e-mail and I will forward on the diagrams that I have for your car. You will need to get over to section 14 (?) as I recall and that will have all the information that you could possibly want to know. Any questions, let me know.

 

Check R2 (relay2) to the left of the break peddle this may have stuck on (failed closed)

This is the auxiliary relay that turns everything off when you remove the key.
this also puts power to F4 a 20A fuse same place as R2

Good luck

 

Ok so I will try to make this as short as possible. I've been troubleshooting this car for about a week now. I decided last night to put a new positive battery clamp on the car. Viola, everything was back to normal for 24 hours. I ran the car in my driveway for 15 minutes the battery cable stayed cool, and the radio was functioning properly. However, I went to drive the car tonight and now I have some major issues. I got about a half mile and pulled over to check the battery cable and it was still fine. I pull back on to the road and go about 200 feet and the car dies. I already knew what the problem was... Let me backtrack on the history of my ownership of this vehicle. almost exactly 1 year ago I bought the car not running. It had an electrical issue that would not allow the car to start. The man I pruchased it from had put a used ECU and TCM in the vehicle. He did not get the ECU programmed, but he also gave be both original units. I got it home discovered F37 fuse to be blown (engine management, blower motor speed module, and road speed sensor) I replaced the fuse and put the stock ECU in the car. Since then it has ran with no issues whatsoever. Now when it stalled tonight I knew that fuse had to be blown, so I put another 15 amp fuse in and it blew again. I put a 30 amp fuse in and drove it home in limp mode which was a very short distance. I am now guessing that it needs another TCM since that is what I believe solved the issue the car had when I purchased it. Thoughts? Very interesting that the car ran for exactly one year and now appears to have the same issue. I bought it on 10/24/14 and the radio issue first appeared on 10/24/15. I think the car is cursed to be honest.

 

jag87, from what you are describing, the problem isn't necessarily the TCM, but another part that is pulling too much current which is leading to the TCM to fail. This is where a tranny shop may be worth your money as they will have the special equipment to see what component is pulling too much current.