No Start - Thoughts?

[Midwestjeepguy]

2018 JLUR 3.6L ESS no e-torque. Drove to work with no codes or issues, tried to start it when leaving at the end of the day and it wouldn't start. All lights, radio, locks, chimes, everything operating as normal other than no start. Only thing on the dash that popped up was a check engine light. No messages, just the normal 'apply brake and press start'. Have a Tazer Mini installed at all times as well as programming done to the PCM via Diablosport i3 tuner. First time anything like this has happened and have never had other electrical issues.

Info to know:
- PCM tuning includes 93 octane, throttle boost, and disable ess from the Diablosport i3 tuner.
- Tazer is used as a fail safe to check codes should they come up and I lowered the tire psi warning. Installed the Tazer around March 2023 and made sure it was updated to latest firmware (11.4.4). Just confirmed that's still the latest firmware.
- New main and aux batteries installed March 2023. Again, no previous issues, but with both batteries 5 years old I didn't want to chance anything.
- Sept 2023 installed new green and white canbus in glove box after reading about what can happen. This was preventative, did not have any issues before or after.

Codes thrown:
P1400 just means the PCM has an aftermarket flash?
U0184-00 lost connect with radio (strange because radio boots up and I can use all the features)
U1514-87 "Engine Controller Secret Code-Missing Message"...umm what?

Troubleshooting:
- Cleared codes then unmarried Tazer and plugged wires back into SGW. Cycled ignition a few times, including two sleep cycles. Still did not start. Codes returned, cleared again.
- Disconnected both main and aux negative cables for 5ish minutes. Still did not start after hooking back up. I unhooked again and it'll remain that way all night.

Next steps (Jeep is still at work, I got a ride home. Didn't have time to do more troubleshooting in the parking lot):
- If hooking battery back up doesn't work, then plug Tazer back in and perform full reboot. Do 2 sleep cycles.
- If that doesn't work, pull high amp fuse array and test to see if any are blown.
- If high amp fuse array is fine, I'm at a loss. Only guess is Tazer is glitchy or alternator is going. I did have the lockers glitch after making some unrelated changes in the Tazer, had to unmarry, full reboot, then marry again to get the lockers to function properly.

Anyone have this same issue before? Other thoughts/ideas on what it could be? Other ways to troubleshoot?

Thanks.

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[Midwestjeepguy]

Bump

Here's what I've done so far and still no start:

- Codes cleared with Tazer, performed reboot, and 2 sleep cycles. Tazer is unmarried.
- Returned PCM and TCM to stock, all tune files removed.
- Checked as many wires as I could to see if any grounds/connections are loose, but I cannot find any. Granted, I'm sure there are some wires I've missed checking as I can't see where everything goes.
- Tested high amp fuse array and all were good. Checked fuses and swapped some relays, everything looked good.
- Checked starter plug/harness for corrosion and it's clean.
- Main battery tested at 62% and aux battery tested at 60%, despite both of them being newly installed in March of this year. Charged both to 100%, still no start.
- Pulled IBS sensor and no start. It did throw a code for that (expected), so I plugged it back in and cleared the code. Hasn't returned with other start attempts so I've ruled this out.
- Ran the aux pos cable to the main aux bank (aux delete) and installed a new H7 battery just in case both batteries have issues they aren't showing. Still no start.
- Planned to get a high output alternator down the road so figured this was as good a time as any in case the factory alt crapped out. Just installed the new HO alt and no start. There is a high pitch whine coming from the alternator when the ignition is turned to run. The original alternator may have made the same noise, I'll reinstall that when I get a chance to see if that is consistent across both of them.

Next steps:

Again, problem is when I push the start button there's one click and it does nothing. Everything has power. Code P1400 shows up every time. Other codes have come and gone, but it's usually only 1 or 2 codes that will show up after I clear everything...sometimes just P1400. So here's where I'm at:

- There's a loose/corroded ground I missed. What are common ones I should check?
- PCM needs to be replaced? I was able to return it to stock with my tuner, does that mean it's still good though? Possibly a bad voltage regulator in it? Would that lead to a no start situation without warning? Would a bad voltage regulator also cause the alternator whine I'm hearing when ignition is on run?
- Bad BCM?
- Bad starter? Seems odd that it would be the starter, it went from zero issues to no start without warning.

 

[frondel]

Bump

Here's what I've done so far and still no start:

- Codes cleared with Tazer, performed reboot, and 2 sleep cycles. Tazer is unmarried.
- Returned PCM and TCM to stock, all tune files removed.
- Checked as many wires as I could to see if any grounds/connections are loose, but I cannot find any. Granted, I'm sure there are some wires I've missed checking as I can't see where everything goes.
- Tested high amp fuse array and all were good. Checked fuses and swapped some relays, everything looked good.
- Checked starter plug/harness for corrosion and it's clean.
- Main battery tested at 62% and aux battery tested at 60%, despite both of them being newly installed in March of this year. Charged both to 100%, still no start.
- Pulled IBS sensor and no start. It did throw a code for that (expected), so I plugged it back in and cleared the code. Hasn't returned with other start attempts so I've ruled this out.
- Ran the aux pos cable to the main aux bank (aux delete) and installed a new H7 battery just in case both batteries have issues they aren't showing. Still no start.
- Planned to get a high output alternator down the road so figured this was as good a time as any in case the factory alt crapped out. Just installed the new HO alt and no start. There is a high pitch whine coming from the alternator when the ignition is turned to run. The original alternator may have made the same noise, I'll reinstall that when I get a chance to see if that is consistent across both of them.

Next steps:

Again, problem is when I push the start button there's one click and it does nothing. Everything has power. Code P1400 shows up every time. Other codes have come and gone, but it's usually only 1 or 2 codes that will show up after I clear everything...sometimes just P1400. So here's where I'm at:

- There's a loose/corroded ground I missed. What are common ones I should check?
- PCM needs to be replaced? I was able to return it to stock with my tuner, does that mean it's still good though? Possibly a bad voltage regulator in it? Would that lead to a no start situation without warning? Would a bad voltage regulator also cause the alternator whine I'm hearing when ignition is on run?
- Bad BCM?
- Bad starter? Seems odd that it would be the starter, it went from zero issues to no start without warning.

Hey,

Did you ever find out what was the problem with your no crank? I am currently facing the same issue in my 2023 JL also PCM unlocked.

 

[Midwestjeepguy]

Hey,

Did you ever find out what was the problem with your no crank? I am currently facing the same issue in my 2023 JL also PCM unlocked.

It was a blown head gasket. Had coolant leaking into the cylinders and it sensed something was off. Don’t ask me why a more obvious code didn’t show for it. All I know is it immediately locks down the engine from turning on.

Maybe that morning I remote started the jeep from inside the house and missed a rough start up and/or smoke coming out of the tail pipe from burning coolant that seeped into a cylinder(s). Drove to work then when trying to start it at the end of the day it sensed enough of an issue to not start.

Entire engine was replaced under an extended warranty. The Jeep dealership fought on my behalf to have it all replaced because they’ve had returns when only the head was swapped for a new one. Guess I got lucky the adjuster agreed with them.

Hopefully it’s not that serious for you. Good luck diagnosing it.

 

[alphawolff]

It was a blown head gasket. Had coolant leaking into the cylinders and it sensed something was off. Don’t ask me why a more obvious code didn’t show for it. All I know is it immediately locks down the engine from turning on.

Maybe that morning I remote started the jeep from inside the house and missed a rough start up and/or smoke coming out of the tail pipe from burning coolant that seeped into a cylinder(s). Drove to work then when trying to start it at the end of the day it sensed enough of an issue to not start.

Entire engine was replaced under an extended warranty. The Jeep dealership fought on my behalf to have it all replaced because they’ve had returns when only the head was swapped for a new one. Guess I got lucky the adjuster agreed with them.

Hopefully it’s not that serious for you. Good luck diagnosing it.

Blown head gasket caused your starter to fail due to momentary hydro lock. We see it a lot.

 

[Midwestjeepguy]

Blown head gasket caused your starter to fail due to momentary hydro lock. We see it a lot.

Ah that makes sense. Now that you say that I think they installed a new starter on the new engine and got that covered as well.

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