Here's a new one...Start Button Fault - McLaren Life
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post #1 of 5 Old 03-20-2017, 12:58 PM Thread Starter
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Join Date: Mar 2016
Location: Austin, TX
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Here's a new one...Start Button Fault

Spent the day at COTA turning several tanks of fuel into brake dust and tire shavings.

At the end of the day, after last session was complete, stopped on pit lane to pack up my stuff. Car would not restart. Message on display was

Start Button Fault - Call McLaren Service Center

Windows were down and ebrake was on. Car was VERY hot, having just come off of track on a high 80-degree day. Center console was also very hot, with the sun directly on it.

Tried lots of ways to reset it. Walk away/sleep/reawaken...OBD scan tool Reset All Codes...disconnect/reconnect dice. Thought I was going to have to leave the car on pit lane overnight with the windows down.

Texts to service personnel at both Houston and Philly (Thanks for the weekend support, guys!) revealed "never seen that one before".

Eventually was able to get the windows up by repeatedly pushing the Start button while holding the window switch up. Didn't work on the ebrake, though.

Finally was able to power-up by sitting in car with both doors closed, and then locking/unlocking. That reset something and the car started. Drove it to garage, turned off and tried to restart. Fault reappeared. Was able to repeat the lock/unlock sequence to start again, but clearly something is amiss.

Anybody ever seen this one before?
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post #2 of 5 Old 03-20-2017, 05:56 PM
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Location: Southern California
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Luckily it wasn't a "stop" button fault.

In all seriousness, I have ran across "hot start" issues in Porsche 944s and the problem was the starter itself, but it seems that in your case you had trouble even turning the key on, right?

Never ran across this on the McLaren, but then again, I haven't tracked it in hot and humid TX.
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post #3 of 5 Old 03-20-2017, 06:15 PM
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I had a similar issue a few weeks ago in my 650... service manager said to hold down brake "hard" and HOLD start button ... that did the trick... and the issue hasn't sprung up since.... (knocking on wood)

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post #4 of 5 Old 03-20-2017, 08:42 PM Thread Starter
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Location: Austin, TX
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Overnight stay in a cool garage and it works as designed again.

So it basically overheated. Texting with a tech at PhillyMac says that all those switches in the pod are a single serviceable electronic unit, not individual assemblies.

I'm going to sit the car out in the sun later this week and see if the problem reappears. I'm also going to carry a can of electrician's freeze spray in the car for awhile...
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post #5 of 5 Old 03-20-2017, 08:51 PM
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That's a new one to me. And I've left the car sitting in BROILING desert sun all across the country, 114 in savanah, 117 near death valley. For hours. Interesting, I wonder what's going on that rattling the other switches gets it to work.

Thanks for sharing the experience, please let us know if you figure out anything further.
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