I am driving a long in my 98 XK8 and....BAM! Every light and whistle goes off. The first time It did this I turned it off the engine (thinking it would reset) and of course it would not restart. I had to get a jump at night, with no working lights, at a stoplight, in the middle of the road! Good thing the battery is in the trunk. When it happens I can limp home, take off the negative terminal, wait, reconnect, then everything is fine until it happens again. It happened a few times three months ago then it did not happen again until now. Please help me pinpoint it.

Here is exactly what is happening. I am using the car as normal then a red oval dash light comes on, then the abs traction light comes on and then the message center usually displays some random message like "driver door open." As soon as all that happens nothing works correctly. Steering is heavy, idle is high, lights do not work, windows work some of the time, radio and ac do not work. If it is put into park it locks op and will not go into any other gear (it is automatic). Also, when this is happening the traction control is on constantly, so you have to punch it to go anywhere. LOL

Any Ideas?

Ok, With the car running, I took off the negative battery terminal and the car died immediately. Does this indicate a bad alternator? That does not make sense. The battery seems fully charged and has never gave me any trouble starting it. Also, the alternator belt is good and tight. Will an alternator fail for a short period then work again? Will the engine charge the battery when the alternator is not working? I would test the alternator but as far as I can tell there is no way to get to the positive terminal on it.

 

There have been a number of posts about loose/corroded connections both in the B+ and Neg cables. Perhaps you could loosen/tighten all the connections through the trunk and under the hood. With the battery in back, there are many more connections involved.

Another thought is the failure of the ECM power relay. It too will cause immediate shutdown. It is the sorta stand alone relay in the ECM fuse panel. Swap with another relay. Almost all the relays are the same.

There was also a recall on the throttle body for you MY. It also caused complete shutdown.

 

Dont pull bat cable off to check for alternator charging. Old school, bad for computer cars.

Check your battery with a voltmeter. 14+ v. is a good charge.

Alternators are either good or bad; not sporadic.

Sounds like electrical connection corroded, faulty ECU or electronic part. Unlikely a mechanical malfunction like vacuum leak, etc.

Have you run any codes?

 

eeeks, good luck man.