Truck Won’t Start w/Button Press - Rare Issue

[MarkrR6754]

I searched the site for starting issues, but none appears to match my scenario.

My Gladiator will often fail to start on the first attempt of the day…but not every day. There appears to be a related condition…the brake pedal is quite firm and doesn’t depress when the failure to start occurs. Nice I encounter the issue I open and close the door, release and reconnect the seat belt. Basically, I try anything different…even release and reset the parking brake.
Everything about the scenario is random. This time if I press and HOLD the Run switch it’ll start. Next time, it won’t.
Yesterday I did all of the tricks. Press to start…nothing; open and close the door…nothing; press and release the shifter lock button. And so on. Then, it suddenly started.
As far as I can tell, this occurs on first start of the day, then I don’t see the problem for a few days, or a repeat on the same day.

I haven’t taken it to the dealership due to the total randomness of the problem. If I can get it to the dealership they won’t experience the problem unless they hold it for multiple days…if at all.

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[punk'n]

Random guess... you are loosing brake vacuum. So your brake pedal is hard and not allowing it to register when you are pressing it to start the truck.

Do you have remote start? When this happens, try to remote start it. If it starts on remote, let it run a few seconds. Then turn it off and try to start normally. Vacuum should have built up enough that the pedal is no longer hard and allows normal start. If this works, you have a vacuum leak on the brakes when it sits.

 

[sharpsicle]

Random guess... you are loosing brake vacuum. So your brake pedal is hard and not allowing it to register when you are pressing it to start the truck.

Do you have remote start? When this happens, try to remote start it. If it starts on remote, let it run a few seconds. Then turn it off and try to start normally. Vacuum should have built up enough that the pedal is no longer hard and allows normal start. If this works, you have a vacuum leak on the brakes when it sits.

I was thinking the exact same thing. That's a great place to start for some troubleshooting. Since none of the other things (Ebrake, seat belt, etc) impact the ability to start, they likely aren't going to be the problem.

The brake sensor being engaged enough to allow it to start could literally be a difference of millimeters. The difference in time would be related to how long it took the pedal to depress just enough with the extra pressure fighting back.

 

[MarkrR6754]

Random guess... you are loosing brake vacuum. So your brake pedal is hard and not allowing it to register when you are pressing it to start the truck.

Do you have remote start? When this happens, try to remote start it. If it starts on remote, let it run a few seconds. Then turn it off and try to start normally. Vacuum should have built up enough that the pedal is no longer hard and allows normal start. If this works, you have a vacuum leak on the brakes when it sits.

That’s a good place to start. Thanks. I tried remote start while sitting in the cab, the truck didn’t start from the key fob, but it did start with the next push on the Start button…so possibly related.
I appreciate the input…that’s what I was hoping for. Always helps to have another input. Hard pedal is always my first clue…you’re on to something.

 

[JeepCares]

I searched the site for starting issues, but none appears to match my scenario.

My Gladiator will often fail to start on the first attempt of the day…but not every day. There appears to be a related condition…the brake pedal is quite firm and doesn’t depress when the failure to start occurs. Nice I encounter the issue I open and close the door, release and reconnect the seat belt. Basically, I try anything different…even release and reset the parking brake.
Everything about the scenario is random. This time if I press and HOLD the Run switch it’ll start. Next time, it won’t.
Yesterday I did all of the tricks. Press to start…nothing; open and close the door…nothing; press and release the shifter lock button. And so on. Then, it suddenly started.
As far as I can tell, this occurs on first start of the day, then I don’t see the problem for a few days, or a repeat on the same day.

I haven’t taken it to the dealership due to the total randomness of the problem. If I can get it to the dealership they won’t experience the problem unless they hold it for multiple days…if at all.

Sorry to hear this, MarkrR6754. We certainly understand that intermittent concerns are difficult to diagnose and can be frustrating. That said, if you do decide to visit a dealer for assistance, we are happy to help you while there. We'll be in private message at any time!

Kate
Jeep Cares

 

[bsd103]

my vote is a voltage issue due to a flaky connection, likely a ground

 

[Kevin_D]

The brake booster vacuum comes from an electric vacuum pump, not manifold vacuum.
When it won’t start, does the START button switch to RUN?

Kevin

 

[MarkrR6754]

The brake booster vacuum comes from an electric vacuum pump, not manifold vacuum.
When it won’t start, does the START button switch to RUN?

Kevin

Yes…it cycles through the functions, then back to off. It hasn’t happened again this week since Tuesday. Next time it occurs I’m going to push the brake pedal harder and see if it starts then. I may end up taking it over to the dealer anyway…once it fails again and I can determine what makes it finally start.

 

[MarkrR6754]

Update: Thanks to the brilliant deductions from punk'n and sharpsickle that put me on the right track. I haven't had a start issue since receiving your inputs. Apparently I have a rather light foot when starting my Gladiator. If it's been recently started, i.e. Soft Pedal, then she stif it arts right up. When the vacuum has bled off over a few days, i.e. Hard Pedal, I merely push the pedal a bit more and she stills starts right up. If I were driving everyday I probably wouldn't have noticed anything.

I'll consider this normal functioning and just concentrate on ensuring the brake pedal moves when I start my Gladiator. Or, is my experience unique, indicating that I have a vacuum leak that should receive service?

Thanks to the nudge in the right direction.

 

[Sgt Gladiator]

I searched the site for starting issues, but none appears to match my scenario.

My Gladiator will often fail to start on the first attempt of the day…but not every day. There appears to be a related condition…the brake pedal is quite firm and doesn’t depress when the failure to start occurs. Nice I encounter the issue I open and close the door, release and reconnect the seat belt. Basically, I try anything different…even release and reset the parking brake.
Everything about the scenario is random. This time if I press and HOLD the Run switch it’ll start. Next time, it won’t.
Yesterday I did all of the tricks. Press to start…nothing; open and close the door…nothing; press and release the shifter lock button. And so on. Then, it suddenly started.
As far as I can tell, this occurs on first start of the day, then I don’t see the problem for a few days, or a repeat on the same day.

I haven’t taken it to the dealership due to the total randomness of the problem. If I can get it to the dealership they won’t experience the problem unless they hold it for multiple days…if at all.

Mark, I’ve started experiencing the same issue with my 2020 Gladiator. The situation is identical to what you have described. The exception is no matter how hard you push on the firm brake pedal, it will not start. The only work around I’ve found is connecting my Jump Box to the battery. When I do that it has freed up the brake pedal every time allowing me to start the Jeep. It stinks having to carry the Jump Box around all the time, but I don’t want to get caught out and not able to start.
I made an appointment with the dealership and it is going in this afternoon. Hopefully they will be able to fix the issue that is causing this.
Fortunately, it is the first big problem I’ve had with it in two years, with the exception of a problem with the original soft top.
Update: Jan. 21, 2022: I got the Gladiator back from the dealership today after dropping it off at the beginning of the week to address this problem and also routine maintenance.
The service manager advised that they diagnosed the starting problem. He indicated that it was a result of both the main & aux batteries being bad. They replaced both under warranty. Since having the Gladiator back I have not experienced the problem again.

 

[AstroZombie]

I have the exact same issue on my 2021. Glad I did s search instead of re-posting another thread about the same issue LOL. I have heard this can be caused by the secondary battery being low or even dead. Has anyone tried to change the little battery used for auto stop?

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