Driving on the highway in the 03' STR. about 70MPH.
Without warning the E Brake slams on, slowing the car from 70 to 10 MPH in about 200 feet IN TRAFFIC! Was able to get to the shoulder, without being rear ended and watch the display, ABS Fault, Brake Fault, Restricted performance...you name it flash by on the idiot screen. The engine was still running, but poorly. After turning off and restarting the engine several times, it began to run properly without the error messages. I still have one error code for the right bank O2 upstream sensor (replaced sensor and keeps coming back, but no other codes?) What the heck could cause something like this to happen? Whatever it is it's about the most dangerous situation that a car....ALL BY ITSELF could try to kill the driver, and wipe the codes and evidence! WTF???

 

Never heard of it, though it is an emergency brake. Not meant to self-apply!

Being electrically operated I suppose you must have an electric fault (maybe more than one). Chafed wiring?

Non - E brakes can also self-apply, but again very rare.

I'm surprised that little caliper & pad can manage the braking you post! Look at the sizes of the other (especially front) ones!!

 

The ebrake was the least of your worries. Find out why the engine suddenly ran so poorly.

Sounds like water-in-the-trunkitis to me, possibly a bad battery also.

 

The E-Brake applying by itself was the worst part! just like slamming on the brakes at highway speed for no reason! I know the Jag computer does not like a low voltage/old battery, the battery is new less than 2 years old. The positive cable was not loose but I could put about two more turns on the 8mm nut, maybe this was the trouble? I may never know. It has not happened in the last three times the car was driven, This should NEVER happen. Just like the runaway Toyota problem in reverse. I can't explain why the error codes disappeared?? Did 007 sneak into my garage and clear them?

 

Even with deliberate park brake application, a car will not stop from 70mph in 200 feet. The engine will easily overpower the brake and the car won't slow down one bit.

Your primary problem was the engine cutting out.

I doubt that your applied it self at all- there was simply a classic 'park brake fault' message along with the others which point to bad battery/water in the electronics.

Typically no codes are registered for these events.

 

Did the rear wheels lock up?

 

Can't remember if the rear wheels locked up. Driver was in panic mode!
I know the car went from 70 to about 10 MPH in a hurry and I bailed into the gravel on the shoulder. I'm thinking it was the battery cable? I need to put someone in the trunk and have them pull the cable at speed to test my theory.

 

I'll pass on being the volunteer for that job, thank you

That would be very scary while driving. Good luck on finding the cause++

 

Nothing will happen except for the battery charge indicator light on the dash.

 

The problem with aplying a rear wheel parking brake at speed is it doesn't slow the vehicle very quickly, even if it is able to lock the rear wheels it will only provide about 15% of the normal braking power, and if the rear wheels locked at 70mph, you would have known about it.

It would be nothing like an emergency stop or even a quarter the power of an emergency stop, and a little gas would overcome the parking brake.

Who rides a bike, what brake do you use to stop,? The front, cos when you use the rear brake it doesn't slow you down or it locks up making you skid, it's the same with a car.

A bit of gas even overcomes the main rear brakes as anyone who holds the car stationary on the foot brake while spinning the rear wheels will know.

 

I'd really like to know what could have caused the car to go berserk on the highway and then behave after a few restarts.
I don't want to go through the experience again.

 

I've never heard of an electronic parking brake coming on, on any vehicle in motion, and I used to be an accident investigator.

Are you sure it didn't just lose power.

 

I guess it could have been complete and sudden loss of engine power.
But then it fixed itself? For how long? Wish I knew what caused it.

 

Have you checked for codes?

 

No codes except the upstream driver side O2 sensor (P1646 I think) that just wont go away even after the sensor was replaced months ago but nothing else.

 

Been reported dozens of times here over the years. I had it once.

Have you opened the trunk to look for water yet?

 

Yes. I opened the trunk to check the battery connections. I didn't open the big black cable box or remove the spare tire. I'll rip the spare tire out and look around some.

 

as others have indicated, the puny ebrake calipers deploying would not stop a car from highway speeds very fast at all,

i would start with the battery and its connections, you don't have to have anyone pull on the battery cables while you drive...

the battery and its connections should be firmly secured to spec, and there should be no excuse for a bad connection there,

would the engine shutting off , with the transmission in drive, suddenly decelerate the car that quickly?

The ABS can deploy individual brakes; was the car decelerated this way?

very odd incident! would start at the battery since that is known to do all sorts of strange things when failing... but this ones an outlier for sure...

 

Have a look here about testing your battery Car Battery Tester - How to Test a Car Battery

 

What is weird, is Ive used the parking brake to hold the car at the drag strip. As soon as the gas is touched the parking brake releases. I know not the best way to do things, but I was trying stuff out