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Discussion Starter #1
I have a 2012 JKU. As the weather has warmed up here (100+ degrees) I've noticed that the Jeep is stalling all the time when I come to a stop at a light. Luckily, it starts right up again. The latest problem is it won't start at all in the mornings now. It's like the battery is completely dead, but if I wait a couple of hours and it warms up outside, it starts up like nothing is wrong.
I just moved to this town in May and took it to a new mechanic for a tune up--the problems started after that. He is out of business due to health issues, so I took it to another mechanic who ran a scope on it and he said there was nothing wrong with the car. He also road tested it and, of course, it ran beautifully. I'm trying to get some idea of what might be the problem before I take it to the dealer as $$ are tight from the move and I want to know what to expect.
I'm super nervous about this as I take this Jeep through some pretty remote places for work and can't afford to be stranded. Help!!
 

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I have a 2012 JKU. As the weather has warmed up here (100+ degrees) I've noticed that the Jeep is stalling all the time when I come to a stop at a light. Luckily, it starts right up again. The latest problem is it won't start at all in the mornings now. It's like the battery is completely dead, but if I wait a couple of hours and it warms up outside, it starts up like nothing is wrong.
I just moved to this town in May and took it to a new mechanic for a tune up--the problems started after that. He is out of business due to health issues, so I took it to another mechanic who ran a scope on it and he said there was nothing wrong with the car. He also road tested it and, of course, it ran beautifully. I'm trying to get some idea of what might be the problem before I take it to the dealer as $$ are tight from the move and I want to know what to expect.
I'm super nervous about this as I take this Jeep through some pretty remote places for work and can't afford to be stranded. Help!!
Hi Lemonjello1,

Has the battery been checked or replaced recently? If we can help make an appointment at your local Jeep dealership, please don't hesitate to reach out.

Kori
Jeep Social Care Specialist
 

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I had a stalling issue on my Focus ST when it was brand new. Coming off the highway, or into an intersection, when I got to the stoplight and pushed in the clutch, it would stumble and die. It was traced back to a faulty wiring splice in the wiring harness, causing the MAP (manifold absolute pressure) sensor to malfunction. The 3.8 and 3.6 engines both use a MAP sensor vs. a MAF (mass airflow sensor). It might be worth trying a replacement MAP sensor to see if that helps with the stalling. If that might be related to it now not wanting to start, I couldn't even guess. Hope you get it sorted out. Please let us all know what the fix ends up being.
 

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Thank you for the suggestions. I have an update: I took it to a battery specialist and he did a load test on the battery (purchased 12/15) & checked the alternator too. Other than a loose connector, everything looked fine. The loose connector might be why I'm having the dead battery issue and it may be unrelated to the stalling issue.
The battery guy said the stalling might be a fuel filter and referred me to another mechanic. That mechanic said that he didn't think Jeeps had fuel filters but to come back at 3 pm for a diagnostic. I'll be sure to mention the MAP problem.
To be continued...
 

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Thank you for the suggestions. I have an update: I took it to a battery specialist and he did a load test on the battery (purchased 12/15) & checked the alternator too. Other than a loose connector, everything looked fine. The loose connector might be why I'm having the dead battery issue and it may be unrelated to the stalling issue.
The battery guy said the stalling might be a fuel filter and referred me to another mechanic. That mechanic said that he didn't think Jeeps had fuel filters but to come back at 3 pm for a diagnostic. I'll be sure to mention the MAP problem.
To be continued...
I would be surprised if it was a fuel filter issue. There are two fuel filters as part of the fuel pump assembly. The filters should last the life of the vehicle. They're not listed as serviceable. It seems like it would be more of an electrical problem. I'm sure they will check for codes. Intermittent stalling can be difficult to diagnose. Hopefully, there's a stored code to point them in the right direction. Also have them check the connections in the Totally Integrated Power Module (TIPM). I've seen where if there was a loose connection(s) in and to the module it has caused the problem you're experiencing. It might not be, but it should be ruled out. Good luck.
 

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Thank you for the suggestions. I have an update: I took it to a battery specialist and he did a load test on the battery (purchased 12/15) & checked the alternator too. Other than a loose connector, everything looked fine. The loose connector might be why I'm having the dead battery issue and it may be unrelated to the stalling issue.
The battery guy said the stalling might be a fuel filter and referred me to another mechanic. That mechanic said that he didn't think Jeeps had fuel filters but to come back at 3 pm for a diagnostic. I'll be sure to mention the MAP problem.
To be continued...
IF you have a loose battery clamp, that would be causing your issues...
 

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Thank you for the suggestions. I have an update: I took it to a battery specialist and he did a load test on the battery (purchased 12/15) & checked the alternator too. Other than a loose connector, everything looked fine. The loose connector might be why I'm having the dead battery issue and it may be unrelated to the stalling issue.
The battery guy said the stalling might be a fuel filter and referred me to another mechanic. That mechanic said that he didn't think Jeeps had fuel filters but to come back at 3 pm for a diagnostic. I'll be sure to mention the MAP problem.
To be continued...
A fuel filter would not cause what you described and you would have a noticeable lack of power and inability to reach higher RPM's. I agree you may have 2 separate issues. Let's see if the loose wire fixes your dead battery problem.

As for the stalling someone else mentioned the air idle control valve or mass airflow sensor (or Jeep equivalent). These should leave behind retrievable codes that will tell us. If worse comes to worse you can measure the voltage at the sensors under different conditions as see if one is failing. The mechanic should be able to help. Neither is a big expense.
 

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Discussion Starter #8
Update

OK, so the latest mechanic is also at a loss as to what is wrong. The good news is that tightening down the battery posts solved the non-starting problem, so it's unrelated to the stalling after all.
The latest mechanic did a complete reset of the system, thinking that might be the fix, but no luck. It still stalls. The dude next door told me to check the "crank sensor positioning switch", so maybe that's worth a shot?
 

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OK, so the latest mechanic is also at a loss as to what is wrong. The good news is that tightening down the battery posts solved the non-starting problem, so it's unrelated to the stalling after all.
The latest mechanic did a complete reset of the system, thinking that might be the fix, but no luck. It still stalls. The dude next door told me to check the "crank sensor positioning switch", so maybe that's worth a shot?
Any of the sensors we've mentioned, MAP (manifold absolute pressure), CPS (crank position sensor) etc., should set a code in the computer. Have any of the "mechanics" that have looked at your Jeep scanned for error codes? Are they seeing any diagnostic codes that you can post here? Intermittent wiring shorts are hard to diagnose, and if they are extremely brief they may not be setting a code, but any sensor that might be seeing incorrect voltages or might be malfunctioning should be setting a code that can be read through the OBDII diagnostic connection on your Jeep.
 

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replace the CPS sensor... The jeeps don't throw codes when the sensors are intermittent.

I had a problem with one of the camshaft position sensors which would cause a rough start 1 out of 10 starts. No code, dealership said they could not reproduce the issue. Bought and replaced the sensor and never had an issue again.
 

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replace the CPS sensor... The jeeps don't throw codes when the sensors are intermittent.

I had a problem with one of the camshaft position sensors which would cause a rough start 1 out of 10 starts. No code, dealership said they could not reproduce the issue. Bought and replaced the sensor and never had an issue again.
Does this CPS sensor cause stalling?
 

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When its about to stall can you rev and keep it running? When you feel it stalling apply the brakes while giving it steady gas and see if still stalls.
 

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I had an intermittent crank position sensor that never threw a code but caused stalling. It's cheap and easy to replace so try that first.
 

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OK, so the latest mechanic is also at a loss as to what is wrong. The good news is that tightening down the battery posts solved the non-starting problem, so it's unrelated to the stalling after all.
The latest mechanic did a complete reset of the system, thinking that might be the fix, but no luck. It still stalls. The dude next door told me to check the "crank sensor positioning switch", so maybe that's worth a shot?
Any update on this???
 
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