Starting Issue

[flyer92]

Having just surpassed 2,500 miles on my 2-door Sport with 3.6L eTorque engine and AT, I recently experienced an odd anomaly that has me both curious and a little worried. When pushing on the brake pedal to start the engine today, I immediately noticed that there was no "give," and the pedal did not move slightly like it should. It was literally rock solid, as if welded in place. During three start attempts, I also a heard a brief scraping noise, similar to when you turn the ignition on an already-running engine (and it clearly wasn't running). After a little more deliberation (and anger) I made a fourth attempt, this time applying a LOT more pressure on the pedal, and the engine started normally. After this occurred, I stopped and re-started the Jeep at least a dozen more times throughout the day and could not replicate the problem. While it is great that everything seems to be working OK for the moment, it has me concerned about future occurrences, possible cause(s), and the notion of being stuck in the middle of nowhere if completely unable to start the vehicle. I have not yet seen a discussion about this issue here on the forums, but just curious if others have experienced the same thing. Please advise...and thanks!

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[Carolina Jeeper]

The vacuum has leaked down in the brake booster after the Jeep has sat. The only thing keeping the vacuum in the booster is a check valve. I've gotten in my Jeep after its been sitting all weekend and brake pedal is stiff, but pressing on the pedal still allows me to start it. Not sure there is an issue with that really. If you have your Jeep running at idle in park with your foot pressing on the brake, turn off the engine. If the brake pedal begins to lift your foot, you have a problem. If immediately after engine shutdown you can press and release the brake several times before it becomes stiff then you are fine. Just my opinion of course since it's almost impossible to properly armchair diagnose car issues.

For the scraping noise, you may have not allowed the engine to fully stop turning before engaging the starter during one of the stop start cycles. That's bad on your part. The starter drive has a difficult time correctly engaging the teeth on the flex plate if it is still moving. Seen this done plenty.

 

[flyer92]

The vacuum has leaked down in the brake booster after the Jeep has sat. The only thing keeping the vacuum in the booster is a check valve. I've gotten in my Jeep after its been sitting all weekend and brake pedal is stiff, but pressing on the pedal still allows me to start it. Not sure there is an issue with that really. If you have your Jeep running at idle in park with your foot pressing on the brake, turn off the engine. If the brake pedal begins to lift your foot, you have a problem. If immediately after engine shutdown you can press and release the brake several times before it becomes stiff then you are fine. Just my opinion of course since it's almost impossible to properly armchair diagnose car issues.

For the scraping noise, you may have not allowed the engine to fully stop turning before engaging the starter during one of the stop start cycles. That's bad on your part. The starter drive has a difficult time correctly engaging the teeth on the flex plate if it is still moving. Seen this done plenty.

Thanks Rollie....really appreciate the insightful feedback. Disappointing that electromechanical anomalies like this are occurring on a new vehicle though. I've owned several other Jeep products with the same/similar ignition system, and never experienced this issue. Although I love my JL, things like this really make me wonder what's coming next, and if I'll be left stranded in the middle of nowhere.

As for the scraping noise, it couldn't have been due to the engine still turning because I wasn't able to start the engine on those first three attempts. Still no idea what that noise might have been, but the Jeep has been running fine ever since (knocking on wood).

Again...thanks for the reply, and happy Jeeping!

 

[LittleDog]

@Carolina Jeeper that was such a great response. Succinct and informative. Basically the opposite of what I post.

I'd just like to add that, if the jeep (or any automobile) is off and parked, and you are inside fiddling with things and maybe step on the brakes once or twice by accident, that can "use up" the free play in the brake.

This jeep has a sensor in the brake pedal that tells it if the brake is depressed to a point where lawyers and legislatures agree that it is safe enough for you to actually start.

If you've used up all your vacuum by accident, or have a leak, and the brakes get hard, pressing down really hard is usually enough to activate the sensor. There's probably a work-around to this that I should look up, print out, and leave in the jeep.

 

[Carolina Jeeper]

Thanks Rollie....really appreciate the insightful feedback. Disappointing that electromechanical anomalies like this are occurring on a new vehicle though. I've owned several other Jeep products with the same/similar ignition system, and never experienced this issue. Although I love my JL, things like this really make me wonder what's coming next, and if I'll be left stranded in the middle of nowhere.

As for the scraping noise, it couldn't have been due to the engine still turning because I wasn't able to start the engine on those first three attempts. Still no idea what that noise might have been, but the Jeep has been running fine ever since (knocking on wood).

Again...thanks for the reply, and happy Jeeping!

You're welcome! Hopefully the anomalies have disappeared. New vehicles can have issues at times with parts that are sometimes imperfect or need to be used several times to get things moving freely.
Although the hard brake pedal can be a bad check valve and fairly easy to diagnose using the method I described. If the brake booster or vacuum line to it are leaking, this might be detected with a vacuum gauge test. Typical vacuum at warm engine idle is somewhere around 18 to 22.
Or you've somehow pressed the brake pedal unknowingly before attempting to start your Jeep giving you the impression something is wrong.
Hopefully nothing continues to be an issue on your new Jeep. I know how annoying that is.

 

[Carolina Jeeper]

@Carolina Jeeper that was such a great response. Succinct and informative. Basically the opposite of what I post.

Thanks! That is my typical response format trying to get directly to the nuts and bolts of an issue.

 

[W Robertson]

Having just surpassed 2,500 miles on my 2-door Sport with 3.6L eTorque engine and AT, I recently experienced an odd anomaly that has me both curious and a little worried. When pushing on the brake pedal to start the engine today, I immediately noticed that there was no "give," and the pedal did not move slightly like it should. It was literally rock solid, as if welded in place. During three start attempts, I also a heard a brief scraping noise, similar to when you turn the ignition on an already-running engine (and it clearly wasn't running). After a little more deliberation (and anger) I made a fourth attempt, this time applying a LOT more pressure on the pedal, and the engine started normally. After this occurred, I stopped and re-started the Jeep at least a dozen more times throughout the day and could not replicate the problem. While it is great that everything seems to be working OK for the moment, it has me concerned about future occurrences, possible cause(s), and the notion of being stuck in the middle of nowhere if completely unable to start the vehicle. I have not yet seen a discussion about this issue here on the forums, but just curious if others have experienced the same thing. Please advise...and thanks!

I had the same "hard brake -no start" issue this past week on my Jeep and found good information on another thread on this site. I joined to share this information with others that are looking for the resolution.
Took it to the Jeep dealership and they tried to tell me I needed a new starter installed for $1648....OMG. I called the service manager and got into a small battle over their misdiagnosis. There are 3 issues that occur -1)hard brake pedal 2)brake lights do not illuminate when pressing 3)vehicle can not be moved out of Park. None of these have anything to do with a starter. He finally admitted there was a brake booster recall in effect and that he would perform this service to see if that corrected the issue. On the invoice it lists "CBXNP141AD Booster -Power Brake" and "CBXNP143AB Kit-Booster. Part #243703".
Picked the Jeep up and haven't had any issues since. Feel sorry for anyone gullible enough to pay $1600 for a new starter, especially when it's not needed.

 

[flyer92]

Thanks for the heads up on this, but I don’t see any open recalls for my 2021. Assuming this is an earlier recall, it should have been completed already.

 

[DeltaWhiskey]

Good information!

I have a 2018 Rubicon JLU, and I have had two instances where my jeep would not start. I don’t remember if there was a hard peddle the first time, but last night when it happened, it did. My experience for both times is that the push button would just cycle ACC, RUN, OFF, with no other action. For everyone reading this, if you have autostart, it will override the issue and start normally. I’ll keep an eye on the brake system now, as this seems logical and fixable.
The first time it happened, I called my dealer, talked for 30 minutes, and all I got was a “never heard of that before, keep us updated.” The two problems have been almost 6 months apart, so I find that odd.

 

[W Robertson]

Good information!

I have a 2018 Rubicon JLU, and I have had two instances where my jeep would not start. I don’t remember if there was a hard peddle the first time, but last night when it happened, it did. My experience for both times is that the push button would just cycle ACC, RUN, OFF, with no other action. For everyone reading this, if you have autostart, it will override the issue and start normally. I’ll keep an eye on the brake system now, as this seems logical and fixable.
The first time it happened, I called my dealer, talked for 30 minutes, and all I got was a “never heard of that before, keep us updated.” The two problems have been almost 6 months apart, so I find that odd.

Same experience with the ACC, Run, Off as well….

 

[W Robertson]

Thanks for the heads up on this, but I don’t see any open recalls for my 2021. Assuming this is an earlier recall, it should have been completed already.

On my first visit (when they told me I needed a starter) I asked if there was a brake sensor recall and they looked on their computer and told me “there aren’t any brake recalls” but when I got into it with the service manager he told me he “found a sensor recall that he could perform for me and not charge me for it.. so all I have to offer is those codes on my invoice. Thanks

 

[flyer92]

Same experience with the ACC, Run, Off as well….

Same here too. Did the dealer ever provide a solution?

 

[flyer92]

On my first visit (when they told me I needed a starter) I asked if there was a brake sensor recall and they looked on their computer and told me “there aren’t any brake recalls” but when I got into it with the service manager he told me he “found a sensor recall that he could perform for me and not charge me for it.. so all I have to offer is those codes on my invoice. Thanks

OK, understand thanks. Seems odd that he just “found a sensor recall,” but glad it at least solved the problem. May I ask what year your JL is, and approximately when this occurred?

 

[joliett]

This same issue just happened to my 2021 Rubicon. So I pressed the brake pedal down HARD and the normal brake pedal feel returned and the Jeep started. My guess...POWER BRAKE BOOSTER and/or MASTER CYLINDER.

 

[mwilk012]

This same issue just happened to my 2021 Rubicon. So I pressed the brake pedal down HARD and the normal brake pedal feel returned and the Jeep started. My guess...POWER BRAKE BOOSTER and/or MASTER CYLINDER.

I'd love to hear your reason for how it could possibly be a fault in the master cylinder. There's nothing wrong with your Jeep.

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