Hey @Mrhead I just PM'ed you my cell. Hit the red dot near the top right & select "Conversations". Click to enlarge, if needed:

 

Hello-we changed the 12v battery and now the car won’t start.... Any suggestions?

Based on 9+ years analyzing every failure report on this forum & the other one, that's quite common.

turned the car in and off 5 times.

"Off" usually only works if it has time to reach "sleep" mode: You have to leave it off for 2 minutes or more, during which no door or hatch is opened OR closed. Any latch mechanism movement can awaken it & you have to restart the 2-min countdown.

It likely just needs to be put to sleep, then disconnect the humidity sensor & 12V negative for 5 minutes & reconnect ONLY the 12V, leaving the sensor unplugged until the end of time, or if you sell the car to someone you hate, since it can kill it.

 

Sometimes a short 12V-only reboot like that doesn't fix it, but there are several more easy things to try, including the following:

• With the car asleep, disconnect the 12V negative for 30+ hours, reconnect & see if it works.
• With the car asleep, disconnect the 12V negative, then unplug the HV fuse under the back seat* for 5 minutes, then replace it, making SURE to have the black handle absolutely vertical when inserting, then reconnect the 12V & see if it works.

* Click to enlarge, or scroll down, whichever shows the red text at the bottom:

 

 

Update:

• @Mrhead unplugged the humidity sensor & left it that way, & disconnected the 12V 5+ minutes.
• That didn't work, so with the car asleep, they disconnected the 12V again & the HV fuse, for 5+ minutes, reconnected HV then 12V.
• That didn't work either so with the car asleep again* they disconnected the 12V then the HV, to do a 30+ hour reboot.

* I think it was asleep, but I don't think that actually matters like the reboot sequence does.

 

@Mrhead loaded the BPCM500e "Jafa" app on a Windows laptop, in case they decide to get an OBDLink.com SX cable to clear any remaining glitches from the 10 "Primary" computer modules.

They also loaded the free AlfaOBD.com "demo" app in order to check the contactors if needed*, & to clear the glitches if "Jafa" won't connect.

* In the unlikely event the contactors are disabled, the ~$60 lifetime AlfaOBD membership will be needed to enable them.

 

Most important though, they're getting surge protection for charging!

 

You are the man!! We can’t thank you enough how knowledgeable you are. You are amazing and I so appreciate all your help. Our Fiat is now ready to drive.

 

Summary:

• 30+hr 12V/HV reboot + "Jafa" * Primary code clear allowed it to drive, but warnings persisted.
• 10 sleeps didn't delete the warnings.
• Sleep, clear, sleep, clear, sleep deleted the warnings.

* BPCM500e app, details in "Jafa App Download" at my "Site Map" (click here).

 

• 30+hr 12V/HV reboot + "Jafa" Primary code clear allowed it to drive, but warnings persisted.
• 10 sleeps didn't delete the warnings.
• Sleep, clear, sleep, clear, sleep deleted the warnings.

btw, this was after the following:

• With no advance warning, the 12V died, which seems to be a common cause of glitches. My theory is it exposes the computers to voltage below their preferred operating range.
• The 12V was replaced with the humidity sensor left connected, which also seems to be a glitch cause.
• Since the car still wouldn't start, a standard OBD tool with its own screen was plugged in, which has been reported to actually kill some 500Es, which is absolutely despicable of Fiat to release a car to the public like that.

In other words, it had a trifecta of glitch causes, & still became drivable after "just" a 30hr reboot & 3 clicks on a free app with a $45 cable.

 

Here's that pic I couldn't find while we were on the phone. It's my own car driving fine even with a big, scary false alarm warning, which you now don't even have any more:

 

LOL! I just noticed the "ESC OFF" warning, but that was due to user input: I turn it off for my favorite onramp before that bridge. It's marked at something like 25mph but I like to take it at about 50

 

A 5-minute reboot/clear might have worked, but it took ~30 hours to ship the $45 cable to clear it.

 

ABSOLUTELY !!!

 

Hi @wraptur & welcome to the group!

Please see "Breakdown Avoidance" at my "Site Map" (click here).