Nothing wrong with doing that- that's part of the design and a key as to why the brake didn't engage on the OP's car. As you said, assoon as the gas pedal goes off the idle position, the brake is released. Since he was driving at 70mph, the gas pedal would not have been at the idle position.

 

That's a perfectly OK way to do it. I think it will only manage a slightly slipping release so will cause a little wear of brakes but so what... (It's designed to be OK if you do it, wear or no wear.)

 

Back to the OP... as people have said the wimpy EPB isn't up to a rapid stop. So, more likely loss of something and electrical power would be a possible, I think. If the EPB was reporting a fault that's typical of it seeing low volts. But you'd have both battery and alternator, so how? Bad ground, maybe?

This one's a real puzzle.

 

Not sure I agree that the EPB coming on, if it did, is the least of his worries as many have said here. If he stopped that quickly, he could have had truck up his chuff in no time.
What if he was on a fast bend? Even a small amount of unintentional braking could result in a slide out.

 

The epb did not come on, he just lost engine power

 

The OP seems quite sure he stopped very quickly. I can't see how losing engine power would do that?
A long time ago, I stupidly pulled the handbrake on a Peugeot 307 on a straight road. In the panic of trying to control the car with a locked up rear end, I couldn't release it and the car ended up spinning around into a ditch. From what I read here, the EPB on a Jag is not able to exert that much grip on the discs?

 

Well... whatever happened, I expect being shocked and desperate to deal with it would plausibly reduce the accuracy of a subsequent post about it.

There might be codes in modules, even if not the PCM (the PCM uses volatile memory but not the others).

 

True. Electrickery is good until it goes bad and cars rely on it so much these days.

 

This is an easy thing to settle.

Test one:

Go out on a deserted road. From a constant speed, let off the gas pedal and start applying the EPB by lifting the handle. First- an alarm will sound. Second- the dedicated indicator on the dash will illuminate. Third- the car will start to decelerate proportionally to how many times the handle is lifted. The rear of the car will squat. If it's lifted a sufficient number of times, the rear wheels will start to lock up, moreso as the car's velocity decreases. The EPB will disengage immediately if the gas pedal is depressed even slightly.

The OP mentioned no alarm, no EPB indicator, no squat and no locking of wheels or skidding.

Test two:

Drive on the same road at the same speed but following another car. Turn the ignition off (not locked). You'll swear the other car must have floored the gas or someone hit the brakes on yours.

 

I don't fancy either option, but if there was an electrical issue with the brake, it may not behave in the way that you describe.
Here's another test. Directly wire up the connector in the trunk for the EPB to the battery and it will lock the brake on solid or release it, depending on the polarity.

If such an electrical issue was to occur on it's own, could it not behave the same even at speed?

Perhaps my mistrust in electrics is coming over too much... ....and my EPB only works intermittently in any case!

 

Same effect as pulling up on the lever minus the warnings.

 

...in which case, it isn't a situation I want to be in at speed as even the throttle over ride may not not work if there is an electrical issue.

If it never happened to the OP then good, because if it was just a shut down of the engine, that won't lock the back up.

 

But the OP did not run a wire directly to his epb, with just rear wheel braking you get very little slow down or locked wheels. I have not heard of any epb coming on at speed on any make of vehicle.

Any vehicles driven wheels will overcome the braking effect of a parking brake

 

I realise that he didn't connect the EPB directly to the battery, but what if a fault arose that replicated that?

As far as rear wheel braking having 'very little slow down or lock up'? In my experience, it was 100% opposite to that, but that was a FWD vehicle granted.

Secondly, it has been reported by some Renault owners that the EPB on their car has applied whilst in motion.

Either way, as has been said the OP may not have had a faulty EPB moment, it was an engine issue.

 

It's hard to see a puny pad only on the rear stopping the car but also you'd have smoke pouring from the locked-on brake surely. And why wasn't it still locked on solidly?

No, the EPB doesn't fit the facts at all.

 

If it was locked on, it wouldn't be smoking - the tyre would be.

I'm not saying that it was the EPB, but with it being electrical it could have been. Lots of threads on various forums regarding odd behaviour which was traced to an unrelated electrical item.

Whatever it was, I'm happy to believe that the EPB would not behave like this, otherwise it would prey on my mind each time I drove it.

 

Test number 3.

Take an early S-type with a hand operated park brake, or really any rear wheel drive car. Drive on an empty rood and apply the park brake without releasing the gas pedal.

Tires continue to turn, car hardly slows down if at all, and smoke will eventually pour from the overheated rear brakes.

Again- doesn't fit what happened to the OP at all.