720S starting issues

[AA121]

Has anyone else had experience of this....?;
Open the car, press the start/stop button once for the dash etc to "wake up". Then, foot on the brake and press the button again to fire the engine...only this second press just keeps putting the dash back to square one instead of starting the car. It's as if the car doesn't recognise that the brake pedal is pressed. Very, very frustrating and more so because it's intermittent resulting in me not trusting whether the car will start whenever I get in it and so I'm avoiding using it.
Grateful for any similar experiences especially if you managed to resolve them yourselves or through a McLaren service provider.
Cheers
Ps. I have tried changing batteries in both sets of fobs
PPs. I really miss old fashioned keys!!!

[davek_964]

In every other instance of this kind of issue I've seen on the various McLaren forums - 99.9% of the time, the solution is "press the brake pedal harder".

[AA121]

Thanks for the reply....hmm OK I thought I was pressing quite hard (and swearing for extra effect) but I'll give that a try!

[xcentric]

this is possibly one of those useless posts, as I don't have a 720s - but on a couple of vehicles I've had, the brake pedal sensor switch gets sticky/unreliable and gives the same effects as you describe. A replacement switch is a few £ (but almost certainly more for fitting) and it may cure the problem.....

[Gunso]

AA121 said:

press the start/stop button once for the dash etc to "wake up". Then, foot on the brake and press the button again to fire the engine...only this second press just keeps putting the dash back to square one instead of starting

One press to wake up the electrics is not required prior to starting the car.

Jump in. Foot firmly on the brake. Press the start button once.

Pressing the start button without your foot on the brakes is the equivalent of ignition on but not cranked with an old fashioned key. What you’d do if you want to check the fuel quantity, or mileage or put the stereo on. Etc etc.

You might just be switching it all on first press and switching it all off second press if the brake pedal pressure is not sensed as sufficient.

[Crazy4557]

The recommended start sequence is by pressing the button once and waiting a ten seconds or so to allow the electronics to wake up and then press again to start. This gives some time that allows everything to complete their own start up procedures.
It's akin to firing up your PC and expecting it to work immediately but they actually need a bit of time to complete the startup procedure before they can function.

[davek_964]

Crazy4557 said:

The recommended start sequence is by pressing the button once and waiting a ten seconds or so to allow the electronics to wake up and then press again to start. This gives some time that allows everything to complete their own start up procedures.
It's akin to firing up your PC and expecting it to work immediately but they actually need a bit of time to complete the startup procedure before they can function.

I've seen that mentioned before - but I admit to never doing that. I get in and start the car, the same as I do every other car I've ever owned - and not noticed any ill effects from doing so.

[Gunso]

Crazy4557 said:

The recommended start sequence is by pressing the button once and waiting a ten seconds or so to allow the electronics to wake up and then press again to start. This gives some time that allows everything to complete their own start up procedures.
It's akin to firing up your PC and expecting it to work immediately but they actually need a bit of time to complete the startup procedure before they can function.

Can’t see that in the manual.

davek_964 said:

I've seen that mentioned before - but I admit to never doing that. I get in and start the car, the same as I do every other car I've ever owned - and not noticed any ill effects from doing so.

I’m the same. Never an issue.

[AA121]

Thanks all for the input.
Really standing on the brake pedal seemed to work. I say "seemed" because it did actually work but I remain slightly skeptical as the problem appears (to me at least) to be intermittent so I guess time and a bit of repetition will tell. As for the 1 stage or 2 stage sequence for starting the car; I think the 2 step thing was something that the McLaren agent told me was best practice so just got in the habit of doing it for fear of having the dashboard lit up with false alarms otherwise.
Thanks again.