EPB and MoT test

[RWD3M]

I know we have a few testers here so would like to ask a question that I probably already know the answer to.

I have a 2017 Jag that has an Electronic Parking Brake that has recently started intermittently throwing up an amber warning on the dash board. It all works perfectly normally when selecting Park (and back to Reverse or Drive), but when the warning is illuminated the switch itself doesn't work. It isn't an uncommon issue and it seems like it doesn't like the cold or damp, so at the moment the warning is on more often than it's off . A new switch is over £100 (which I could do without spending) and whilst I suspect it's likely just moisture ingress, i'd prefer to replace it than try to dry it and clean it, only for it to fail again, knowing my luck, probably as I take it to the MoT test station!

SO my question is, is this a straight forward fail or just an advisory on a test?

Like I said, I suspect I already know the answer.

Cheers all.

 

[doubleboost]

As long as it meets the efficiency requirements it would be pass / advise.

 

[welder_dave]

So, if the warning light is on the switch doesn't apply/release the parking brake?

If that's the case during a test its a fail on 2 counts.
Sections 1.1.6d and 1.1.6e in the manual.

Parking brake control missing, defective or inoperative - Fail Major
Electronic parking brake MIL indicates a malfunction - Fail Major

Just hope the light is off and it behaves when tested.

 

[RWD3M]

So, if the warning light is on the switch doesn't apply/release the parking brake?

Hi Dave,

Yes, exactly that, despite it functioning perfectly on the gear selector (auto obviously).

I expected that might be the answer

 

[RWD3M]

As long as it meets the efficiency requirements it would be pass / advise.

I'd hoped that might be the answer

 

[doubleboost]

Naturally if the brake wont operate uit is a fail

 

[RWD3M]

Naturally if the brake wont operate uit is a fail

That's the nuisance, it works on the gear selector (i.e. go into park and the brake applies) but not on the switch with the warning on.

 

[doubleboost]

I stand corrected light on or not working major fail

 

[roblane65]

I maybe shot down in flames here , but aren't the park in an auto box and an epb two totally separate systems ? the box park being an electro / mechanical system that prevents the box rotating and being started in gear whilst the epb works on the rear brakes . I've only ever had on motor with epb ( Tiguan ) which I never worked on as it was a lease vehicle .

 

[RWD3M]

I maybe shot down in flames here , but aren't the park in an auto box and an epb two totally separate systems ? the box park being an electro / mechanical system that prevents the box rotating and being started in gear whilst the epb works on the rear brakes . I've only ever had on motor with epb ( Tiguan ) which I never worked on as it was a lease vehicle .

Hi Rob,

It's a bit of both. The box does indeed 'lock up' but at the same time, a signal is sent to the EPB which applies that too.

It's why, for example, when replacing the rear brake pads, you have to put the EPB into maintenance mode and the gearbox into neutral.

 

[roblane65]

Well you learn every day now come to think of it the tiguan did the same , I hated that car ! I'll take old tech any day .

 

[RWD3M]

.... I'll take old tech any day .

I'm with you on that one!

 

[Justme]

Hi Dave,

Yes, exactly that, despite it functioning perfectly on the gear selector (auto obviously).

I expected that might be the answer

Does the parking brake actually apply via the gear shifter or is it just the parking pawl engaging?

 

[premmington]

Warning light on for EPB is a Major Fail - even if you get efficiency requirements on the rollers.

Manual handbrake not so clear - if brake warning light is for another part of the braking system - fluid level - pressure assistance - it is a fail (but who would know - so it is pass and advise for a manual hand brake warning light).

 

[Wedg1e]

Can you apply an EPB while the vehicle is moving? Because the 'handbrake' is supposed to be a secondary form of braking. If the electronics decided applying the EPB was unsafe and the main brakes had failed you'd be stuffed.
Granted most handbrakes will only slow you down at best (ignoring the Jaguar setup which is likely to see the friction material part company with the backing plates - I've seen it happen on an MOT, how that would stop a runaway 2-tonne Jag is a mystery).
I thought most people used the Yanks' method of applying the transmission brake on an auto anyway...
My chief had a Landrover of some flavour when the EPB first appeared, it kept getting stuck on. While LR were awaiting a solution their advice was just not to use it.

 

[willie.macleod]

Can you apply an EPB while the vehicle is moving? Because the 'handbrake' is supposed to be a secondary form of braking. If the electronics decided applying the EPB was unsafe and the main brakes had failed you'd be stuffed.
Granted most handbrakes will only slow you down at best

My chief had a Landrover of some flavour when the EPB first appeared, it kept getting stuck on. While LR were awaiting a solution their advice was just not to use it.

The land rover EPB is a very clever bit of kit and it can be applied while moving (emergency only), it will use the ABS modulator to slow the vehicle as quickly as it can reading all the sensors, it will also apply the rear drum brakes via the electric motor/Bowden cable setup and it monitors the tension the cables are under and the effect slowing down the rear wheels and adjusts accordingly.

It's now a 20 year old system and pretty well proven, certainly when the drums and cables are maintained it works very well giving confidence to the driver on steep hill starts/stops especiallywith trailers attached. It actually monitors the vehicle for a bit when parked up and can increase the cable tension if it sees the force dropping or the vehicle starting to move. It doesn't like servicing being neglected, there are very good guides out there for DIYers and all the bits are readily available.

 

[RWD3M]

Does the parking brake actually apply via the gear shifter or is it just the parking pawl engaging?

Yes, the parking brake applies.

 

[ukracer]

Well you learn every day now come to think of it the tiguan did the same , I hated that car ! I'll take old tech any day .

Now you tell me..lol

 

[RWD3M]

Can you apply an EPB while the vehicle is moving? Because the 'handbrake' is supposed to be a secondary form of braking. If the electronics decided applying the EPB was unsafe and the main brakes had failed you'd be stuffed.
Granted most handbrakes will only slow you down at best (ignoring the Jaguar setup which is likely to see the friction material part company with the backing plates - I've seen it happen on an MOT, how that would stop a runaway 2-tonne Jag is a mystery).
I thought most people used the Yanks' method of applying the transmission brake on an auto anyway...
My chief had a Landrover of some flavour when the EPB first appeared, it kept getting stuck on. While LR were awaiting a solution their advice was just not to use it.

Firstly, I have no idea, I've never tried.

There is no history of Jaguar brake pad material parting company any more than any other manufacturer. Jaguar don't make brake pads, like all other car makers, they buy them in. Currently from Brembo I believe.

No parking brake is meant to stop a 2 tonne car (my Jag is only around 1600 kgs, Aluminium bodied), that's why they are called parking brakes and not runaway stopping brakes

 

[bricol]

No parking brake is meant to stop a 2 tonne car (my Jag is only around 1600 kgs, Aluminium bodied), that's why they are called parking brakes and not runaway stopping brakes

Errrr . . . .

If the parking brake is also the secondary braking system, then it is indeed meant to stop your 2 tonne brick, requiring a minimum efficiency in doing so.

If it does have a secondary braking system, then yes, the parking brake is only required to hold it on a 16% slope.