2002 XK8 lost power on freeway
 

You guys have been a wonderful source for help in the past, so hoping you can help again!

I was driving my 2002 XK8 with 98K mile home in 30mph traffic on freeway. I noticed that my dash lights seem to be dim, but the volt meter looked fine (right in the middle). Then, all the electrical shut off! Headlights, taillights, brakelights, dash lights, stereo, everything electrical, but the car continued to run, but just barely and the tack continued to work but all the other gauges shut off. I was able to get to the side of the road and put the car in park (bad idea since without power, you can't get it into neutral to tow!). Tried to start and nothing. Lights barely came on. No starter solenoid click. Nothing. even the emergency flashers barely worked. Waited a few minutes, tried again and it was better. Waited a few more minutes and the car started and ran, but there was still no electrical, and I still could not get to car out of park. Then it died again. Called the tow truck. He hooked a jumper up and we got enough current to get the car out of park. After the car was home, I started it up and it ran fine. I did notice it took a lot longer for the volt meter to go to center, but it eventually did.

So, before I start dumping money into batteries, alternators, etc. I was wondering if anyone can point me in the right direction, understanding that this is a Jaguar and all electrical issues tend to be mysteries :)

To answer some questions ahead of time. I bought the car from the original owner about 2.5 years ago with 79K. As far as I know the battery and alternator are original. The battery looks in good shape, but hard to tell since it sits in the trunk. If it is original, than I'd think that's the problem! The original owner never told me if he replaced it or not.

I've also noticed that, at night, with the auto climate control on (e.g. A/C), fog lights on, and sitting at idle, turning on the rear window defroster will pull the volt needle just slightly off of center. Getting some RPMs will bring it back. I just figured it was a lot of load and the Alternator can't keep up at low RPMs

Also, since I've had the car, I've had the problem with the intermittent ABS/TRACK lights. I pulled the ABS controller module and did the repair outlined in this forum and that seemed to fix it for about six months, but it came back. Don't know if that is an indicator or not. I just may not have soldered the joints well enough.

Over the last three months, I've had intermittent airbag warning lights. Flashing code is 49, which indicates a sensor in the driver seat. I've done nothing to troubleshoot that.

Finally, I did put the Real Gauge mode in the car, which I love.

That's all the mods and symptoms. Let me know what you think!!!

Thanks,

Ed

Hi Ed-

As a starting point, remove the battery and bring it to Autozone, Advance Auto or Sears for a load test.

Even if it passes, see if you can find a date code on it. If it is over 7 or 8 years I would replace it anyway.

PS: Glad you are happy with your RealGauge!

I've replaced my alternator on my xk8 already, they don't last forever.

Sent from my Epic 4G using IB AutoGroup

I'd bet my bottom dollar that your alternator is fried. I had a very similar experience about 6 months ago. I was driving the freeway in heavy traffic, started getting warning lights, and since I was stopped I tried to restart the car to clear warnings. It was completely dead, no lights, no accessories, no start. After sitting dead for about 15 minutes, I got the car started, and got off the freeway, to my uncle's house nearby where the car died in the driveway. Rebuilt alternator and it's been good ever since.

I had ABS light on forever. Replaced the battery, took wheels off to check brakes, etc. ABS light went away.

Maybe some of that is helpful?

Sandy

Thanks for the ideas!
 

Thanks everyone! I'm going to buy a new alternator and battery tonight and replace them both over the weekend. Might as well start off fresh! I've had bad alternators take out good batteries on other cars, so I've gotten in the habit of changing both just to make sure one doesn't take out the other.

I was glad to get some confirmation that it was something "simple" like the battery/alternator. I was more worried that this may be some other electrical gremlin that would require specialty diagnostics.

I've read in this forum that a weak battery is also a cause for the ABS light issue, so I have been suspect of that too. I'll be really interested to see if the Airbag warning light goes away. It would make sense that a weak signal across a seat sensor that has gone through 10,000 cycles would cause a problem. I'll report back on my progress.

Cheers!

New Alternator and Battery
 

Well, I replaced the alternator and battery this weekend. The alternator wasn’t too bad. It’s a tight fit from the top, but after taking the air box and the air box bracket out, it was just a matter of rotating it the right way. The older alternator looks like an original Jaguar part (has Jaguar labels all over it), and had a lot of greasy dirt plugging up the vents, particularly around the front. So, I suspect this was the original and after 99K miles, I shouldn’t be too upset about that!

I also found out that I’m missing the lower part of the air ducting for the alternator. The part that is bolted to the engine is there, but I guess there is a piece that should goes forward of that sits below the oil filter. Probably need to replace that!

The unfortunate thing is that the battery didn’t fix the ABS or Airbag lights! So it looks like more troubleshooting needed there.

It’s a good thing I love these cars and have the mechanical skills to deal with them! There is just something about driving a Jag!

Thanks everyone for your help. I’ll post again if anything changes.

There are several common causes for the abs light. Dirty sensors or a broken cable first to check. Here is a trouble shooting sheet:

http://jagrepair.com/images/AutoRepa...heet%20XK8.pdf
Note that resistance of sensors is often 1000-1040 ohm.

After that a strong possibility is the solder connection on the circuit board to the abs pump:
JagRepair.com - Jaguar Repair Information Resource

Glad to hear your new alternator solved the problem. But be sure to replace the broken alternator vent duct/ air scoop ASAP, the loss of these can fry an alternator in weeks.

regards