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[SilverUri]

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[KingKona]

I'd be interested in hearing form other 401/401A LCD dash owners, to see if that's just how they work.

 

[SheepDog]

Hi, my name is Damian and I am from Poland. I bought crashed American version of a 2020 Mustang GT premium pp1 and repaired it by myself. I love this car!
(Link to video added)
‍🩹 I need your help with my problem: The car only starts without turning ON the ignition first. When I turn the ignition on and then want to start the engine, the ignition just turns off instead of starting the engine. Could the reason be that the car is set in the system via forscan, for example? Or is it some kind of glitch?

Ps. It's great to join the Mustang family.

I think it is supposed to do that, so that you can turn the accessories on and off without starting the engine. What happens when you press and hold the start button for a second instead of quickly tapping like you do?

 

[SheepDog]

I have been trying to diagnose the problem for a week and have looked for many solutions. No matter how long I press the button, the effect is always the same - the ignition turns off.

What sort of damage did the car have?

 

[luca1290]

Hello Damian,

it's very strange indeed. That is not the correct behavior from the car.
Do you have any DTC stored in the car?
You can send me your AsBuilt data (enter in the various ECUs and backup their config via Forscan) and I can compare with mines and find the difference, if there is some coding involved that should surface it.

 

[Cobra Jet]

I think it is supposed to do that, so that you can turn the accessories on and off without starting the engine. What happens when you press and hold the start button for a second instead of quickly tapping like you do?

Correct. Car won’t totally start unless brake pedal is depressed (automatic) or clutch pedal is depressed (manual) and user holds in the start button (not just tapping it). If the user taps the button, it activates the accessory setting without starting the car.

Also check to make sure the brake pedal (or clutch pedal) “bumpers” are not missing. If they are, or have become deteriorated, that will also cause starting issues. The threads for that topic is here:
https://www.mustang6g.com/forums/th...edal-bumper-nhtsa-recall.172153/#post-3670904

and

https://www.mustang6g.com/forums/threads/brake-light-switch-near-pedal-failure.122100/


——

Also not knowing the extent of the crash damages or how the vehicle was repaired, here’s info I had put together for others who buy salvaged S550’s and repair them. The subject matter is related to the SRS system, because if any of the SRS sensors were tripped, there are procedures for resetting.

----

This is the other diagnostic info I had posted a while back for folks rebuilding salvage S550's with airbag or non-start issues. The info within may also be helpful.
https://www.mustang6g.com/forums/th...cident-or-salvage-repair.165362/#post-3364334

----
Check these 2 areas for SRS issues, threads below for reference.

Knee air bag connections:
https://www.mustang6g.com/forums/threads/2018-gt-airbag-light-on-cluster.107200/page-3#post-3333786

Overhead map light air bag "jewel":
https://www.mustang6g.com/forums/threads/2018-gt-airbag-light-on-cluster.107200/page-2#post-3017970


The S550 airbag system is very complex and any hard fault code reset needs to be performed using a proper scan tool that is equipped to reset air bag codes OR reset by a Dealership using the Ford IDS system. I'm not sure if the SRS system can be reset using the Forscan device. The below charting was applicable to the 2015-2017’s. Some may still be applicable to the 2018+, but there have been many production changes after 2017 so use caution.

 

[Torched10]

Mine a 2019 pp1 starts by pushong down the brake pedal then pushing down rhe start button and holding it I still starts. I did what you say your doing and mine does same thing a as your turns off ignition so just put foot on brake pretty hard then push start button and hold it down and it should start every time

 

[CrazyHippie]

Correct. Car won’t totally start unless brake pedal is depressed (automatic) or clutch pedal is depressed (manual) and user holds in the start button (not just tapping it). If the user taps the button, it activates the accessory setting without starting the car.

Also check to make sure the brake pedal (or clutch pedal) “bumpers” are not missing. If they are, or have become deteriorated, that will also cause starting issues. The threads for that topic is here:
https://www.mustang6g.com/forums/th...edal-bumper-nhtsa-recall.172153/#post-3670904

and

https://www.mustang6g.com/forums/threads/brake-light-switch-near-pedal-failure.122100/


——

Also not knowing the extent of the crash damages or how the vehicle was repaired, here’s info I had put together for others who buy salvaged S550’s and repair them. The subject matter is related to the SRS system, because if any of the SRS sensors were tripped, there are procedures for resetting.

----

This is the other diagnostic info I had posted a while back for folks rebuilding salvage S550's with airbag or non-start issues. The info within may also be helpful.
https://www.mustang6g.com/forums/th...cident-or-salvage-repair.165362/#post-3364334

----
Check these 2 areas for SRS issues, threads below for reference.

Knee air bag connections:
https://www.mustang6g.com/forums/threads/2018-gt-airbag-light-on-cluster.107200/page-3#post-3333786

Overhead map light air bag "jewel":
https://www.mustang6g.com/forums/threads/2018-gt-airbag-light-on-cluster.107200/page-2#post-3017970


The S550 airbag system is very complex and any hard fault code reset needs to be performed using a proper scan tool that is equipped to reset air bag codes OR reset by a Dealership using the Ford IDS system. I'm not sure if the SRS system can be reset using the Forscan device. The below charting was applicable to the 2015-2017’s. Some may still be applicable to the 2018+, but there have been many production changes after 2017 so use caution.

Dude! You're like the Mustang Encyclopedia! What a true blessing to the Forum. Thanks for taking the time to pull this together!

 

[shogun32]

at least you have both key fobs, yes?

 

[SheepDog]

Yes, one admin key and 1 additional one that came with the car.

Any damage to the brake pedal switch/wiring from the crash? (the one attached to the brake pedal linkage)

 

[SheepDog]

The pedal works without any problems, the car starts and brakes normally, and the impact theoretically had little chance of damaging the cables. Forscan shows no errors.

Considering that the knee bolster airbag deployed, it could have damaged stuff in the footwell. I didn't mean the pedal itself, I meant the switch connected to it, that operates the brake lights, unlocks the shifter, and allows the ignition switch to operate

 

[shogun32]

Not a crashed gt, but my 200a 6mt starts immediately from "full accessory mode" as long as the clutch is depressed like any other time.

So does my 300a 6mt

It's your car. Be it wire or sensor, or operator error.

I grok the question in the abstract, but if the car starts from powered off, I don't get the fascination with this particular failure mode.

 

[Torched10]

You said it starts if you dont press start button first,so don't see your concern.just step on brake first then press start button that's always the way I've done it even when I had 2 shelbys one six speed.push clutch in press start button car.starts did you replace fob battery

 

[SheepDog]

the battery will not be able to produce a sufficient spark and the car simply decides to turn off?

No, but a loose connection might

 

[ORRadtech]

My '18 w/o the digital dash starts from the accessory mode with foot on the brake and a touch of the start button- no long press needed.

I grok the question in the abstract, but if the car starts from powered off, I don't get the fascination with this particular failure mode.

You said it starts if you dont press start button first,so don't see your concern.just step on brake first then press start button that's always the way I've done it even when I had 2 shelbys one six speed.push clutch in press start button car.starts did you replace fob battery

I get it. If it were mine I'd want it to behave as it was intended. It would bother me no end until I figured it out.

Sorry OP, I've got nothing to help. It does sound like shogun32 has a good place to start looking with the under dash wiring. That airbag is suspiciously close to a lot of wiring and connectors that could affect starting.
Good luck.

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