2018 JKU Intermittently fails to start TSB 21-041-18

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bobgoats

New member
My 2018 JKU built 3/18 has 5k miles. It has randomly failed to start. It usually happens if I drive for 20 minutes, stop and try to restart within 5-10 minutes.
If you turn the key forward it simply fails to turn over.

I have looked at all the obvious possibilities and found a few things pointing towards this service report "TSB 21-041-18" It related to the vehicle failing to start after warming up. It called for the replacement of the transmission valve body/electrohydraulic control unit.

I was wondering if anyone knew where you can find an actual copy of this report and if anyone has had this same issue and if this repair helped.

Cheers :beer::beer:
 
wjtstudios

wjtstudios

Hooked
First of all, welcome.

Before going down paths like that, start by making sure both your battery cables are tight and that the battery is in good working order. Intermittent starts like that can be commonly traced back to that.


2015 JKUR AEV JK350
1985 CJ8 Scrambler
 
WJCO

WJCO

Meme King
Is the engine cranking but not starting? Or does it not even crank at all and just clicks?
 
cozdude

cozdude

Guy with a Red 2-Door
I would take it to the dealer. If it does happen to fall under the tsb then the trans module will be replaced under powertrain warranty
 
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bobgoats

New member
WJCO said:
Is the engine cranking but not starting? Or does it not even crank at all and just clicks?
Click to expand...


It doesn't turn over at all. No click,,,,after about 10 minutes when it cools down it will start. It has never failed to start when it is cold.
 
cozdude

cozdude

Guy with a Red 2-Door
bobgoats said:
It doesn't turn over at all. No click,,,,after about 10 minutes when it cools down it will start. It has never failed to start when it is cold.
Click to expand...

Could be to high resistance in the power wire to the starter or the starter itself gets so hot that it causes to high of a resistance that it impedes the current flow
 
Noble Woodsman

Noble Woodsman

New member
bobgoats said:
It doesn't turn over at all. No click,,,,after about 10 minutes when it cools down it will start. It has never failed to start when it is cold.
Click to expand...

I had this exact issue in my '96 XJ. It turned out to be the crankshaft position sensor. As i noted above, these are Hall Effect sensors which tend to fail when they are warm, but will function fine after cooling down. I presume the sensor works the same in the new jeeps as well. In my case, i was able to restart the engine after waiting ten minutes, but it would also randomly stall the engine after running a while.


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bobgoats

New member
Noble Woodsman said:
I had this exact issue in my '96 XJ. It turned out to be the crankshaft position sensor. As i noted above, these are Hall Effect sensors which tend to fail when they are warm, but will function fine after cooling down. I presume the sensor works the same in the new jeeps as well. In my case, i was able to restart the engine after waiting ten minutes, but it would also randomly stall the engine after running a while.


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Click to expand...
Thanks for that. I'm gong to get an appointment to bring it in. I will report back when I get it back. Maybe this info can help someone in the future.

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