Last edit 9/28/22. List of edits & credits at the bottom. Sorry if I missed anyone (PM me if I did).
The 500e sometimes shows a warning or error even when everything is working fine, & sometimes something won't work JUST due to an erroneous code.
There are really only 6 things to try. Here's the list, with details below:
1. FIRST check for recalls AND "campaigns". Do NOT use the NHTSA site, since it shows only recalls, NOT the critical U69 "campaign". Go to Mopar.com to enter the VIN, or click here: Lookup FCA Vehicle Recalls by VIN | Official Mopar® Site. Recalls are free at ANY FCA dealer (like Dodge, Jeep, Ram...).
2: If the humidity sensor has been left unplugged, skip to #3. If not, do NOT skip this step!
It’s just right of the rearview mirror, reduces range, & causes many false alarms, some of which make the car die. Put your middle fingers in each opening near the top & pull perpendicular from the glass. Click to enlarge:
If there's no sensor there, you need to dig it out of the headliner where it was stuffed when the windshield was replaced.
With a tiny screwdriver or round toothpick parallel to the glass, stick it straight into the black socket to wedge it open & remove the purple plug. If the car still won't work, continue with #3 below.
Even though you should always LEAVE it unplugged, the cover fits, with its left side hooked on & then the right side snapped upward perpendicular to the glass. Hook/snap points circled in pic.
3: If you hear a little "clunk" or "da-dunk" when you open the left door, skip to #4. If not, do NOT skip this step!
No clunk means the 12V starter battery isn’t activating the High Voltage battery contactors, as needed to charge or start the car. IF you wait several seconds after opening the door, to hear the disconnect clunk, THEN there should also be a clunk:
Grab each end of the black plastic motor cover & yank it straight up like you’re lifting a laundry basket full of wet clothes. It’s almost unbreakable, but completely useless, so I leave mine in my garage closet. Even if the battery passes a parts store load test, the voltage can still be too low, so you have to check it, at the wires, in case the connections are bad:
Left, Amazon "multitester", starting at $10.
Center, $22 BatteryTender.com gauge.
Right, $25 Amazon "bm2"
Just like a gas car, a low 12V starter battery is the most common cause of failure. Even when a 500e is "dead" by gas car standards it will usually start, but sometimes with errors. It can fully die with no warning after only 2 years of normal use, & after that it sometimes won't even jumpstart, so it’s best to have a $25 "BM2" with one of the alarms set at 30%, since it starts reliably with 20%:
B) Enable the contactors with the $50* AlfaOBD app from Google Play Store. The contactor disable glitch is VERY rare compared to “A” above.
If you only have an iPhone/iPad, try a laptop/tablet, or ask your friends if they have an old Android, or get one for $15 on Amazon. No service needed, just download the app on WiFi. A $17 eBay ELM327 KONNWEI KW902 will connect it to the car:
*1 user reported the free "demo" app worked, but then 2 others reported it didn't.
4: "Clear Faults" AFTER steps 2 & 3 above, with OBD or multiple key cycles.
(pic from my own perfectly-working 500e)
Some users say OBD sometimes needs clearing 2 or more separate control units, 2 or more times each, before it stays clear, but maybe they just didn't notice tiny on-screen instructions for special key-positions such as "stop", "mar" or "avv" required to clear some faults:
If you don't have OBD, codes will often clear with the key off for 3 minutes. Repeat if needed, up to 10 times, but usually ONCE works for me, & the most I've ever needed is 3 times, off for just 1.5min for the screen to go fully black (not just really dark grey), but other users report needing 3 min, 5-10 times.
5: Reboot via 12V disconnect AFTER steps 2 & 3 above, & after the key is off for 3-min without opening or closing either door or hatch. A 30-second 12V disconnect worked for me, but when that failed for other users, & so did 30 minutes, 30 hours worked. Ideally, disconnect the NEGATIVE, since it’s more robust, & it won’t short out the 10mm wrench (or even pliers, in a pinch) on any surrounding metal. Retighten it until it won't twist off of the post by hand.
6: Reboot via HV disconnect AFTER steps 2 & 3 above. If your car works, do NOT try this unless you have $50 AlfaOBD in case #3B is needed:
a) Open the hood & left door & don't open or close anything else* for the entire process, to avoid "wake up" signal.
b) Remove the key, wait 3+ minutes for "sleep" mode.
"Click to enlarge" version:
c) Remove the orange plug, disconnect 12V 30+ seconds, push the white part to open the black part 90º, to the center of the orange part, then replace the HV plug, then reconnect 12V.
IF that doesn't work, repeat #3B above.
Some users say that a different sequence is required, but it may just be that they didn't get it quite right the first time. There are at least 3 other sequences, but for ANY of them make SURE to first ALWAYS do steps A & B above, check car function after each one, & repeat #3B, before you continue:
c2) Disconnect HV 30+ seconds & reconnect. Disconnect 12V 30+ seconds & reconnect.
c3) Disconnect 12V, disconnect HV 30+ seconds & reconnect, connect 12V.
c4) Disconnect HV, disconnect 12V 30+ seconds, reconnect, wait 3 minutes, reconnect HV.
* I thought that only the left door woke it up, since it's the only one that awakens the HV systems (contactor clunk), HOWEVER the other door and even the hatch can awaken the 12V systems (instrument screen lights up).
7th edit 9/28/22: Copied 2 thru 6 straight off "dead 500e" post, but warning added to #6.
6th edit 9/25/22: #3A replaced jumpstarting with BM2
5th edit 9/23/22: #4 Onscreen fineprint, thanks to @jedwards1654
4th edit 9/3/22: #6 Press the white HV lock to open the black arm 90º, thanks to @rxd24
3rd edit 8/25/22: #6 Lock WIDE open before HV fuse insertion
2nd edit 8/22/22: #2B needs PAID version of AlfaOBD, & #6 can require #2B after
Edit 12/24/21: #2B "Contactor Glitch" added, thanks to @MDMTahiti & @witmannerik (for confirming it worked)
Credit for #6c2 to RatfinkHarley & BoggleMe on the other forum.
The 500e sometimes shows a warning or error even when everything is working fine, & sometimes something won't work JUST due to an erroneous code.
There are really only 6 things to try. Here's the list, with details below:
- Check for recalls.
- Leave the humidity sensor unplugged.
- Check for "clunk".
- "Clear Faults" with OBD or multiple key cycles.
- 12V battery disconnect.
- HV battery disconnect (all 4 different sequences).
1. FIRST check for recalls AND "campaigns". Do NOT use the NHTSA site, since it shows only recalls, NOT the critical U69 "campaign". Go to Mopar.com to enter the VIN, or click here: Lookup FCA Vehicle Recalls by VIN | Official Mopar® Site. Recalls are free at ANY FCA dealer (like Dodge, Jeep, Ram...).
2: If the humidity sensor has been left unplugged, skip to #3. If not, do NOT skip this step!
It’s just right of the rearview mirror, reduces range, & causes many false alarms, some of which make the car die. Put your middle fingers in each opening near the top & pull perpendicular from the glass. Click to enlarge:

If there's no sensor there, you need to dig it out of the headliner where it was stuffed when the windshield was replaced.
With a tiny screwdriver or round toothpick parallel to the glass, stick it straight into the black socket to wedge it open & remove the purple plug. If the car still won't work, continue with #3 below.
Even though you should always LEAVE it unplugged, the cover fits, with its left side hooked on & then the right side snapped upward perpendicular to the glass. Hook/snap points circled in pic.
3: If you hear a little "clunk" or "da-dunk" when you open the left door, skip to #4. If not, do NOT skip this step!
- When you turn the key on, & another clunk several seconds after you turn it off.
- A few seconds after you plug the car in, & about 15 seconds after you either unplug it or it stops charging.
Grab each end of the black plastic motor cover & yank it straight up like you’re lifting a laundry basket full of wet clothes. It’s almost unbreakable, but completely useless, so I leave mine in my garage closet. Even if the battery passes a parts store load test, the voltage can still be too low, so you have to check it, at the wires, in case the connections are bad:

Left, Amazon "multitester", starting at $10.
Center, $22 BatteryTender.com gauge.
Right, $25 Amazon "bm2"
Just like a gas car, a low 12V starter battery is the most common cause of failure. Even when a 500e is "dead" by gas car standards it will usually start, but sometimes with errors. It can fully die with no warning after only 2 years of normal use, & after that it sometimes won't even jumpstart, so it’s best to have a $25 "BM2" with one of the alarms set at 30%, since it starts reliably with 20%:

B) Enable the contactors with the $50* AlfaOBD app from Google Play Store. The contactor disable glitch is VERY rare compared to “A” above.
If you only have an iPhone/iPad, try a laptop/tablet, or ask your friends if they have an old Android, or get one for $15 on Amazon. No service needed, just download the app on WiFi. A $17 eBay ELM327 KONNWEI KW902 will connect it to the car:


*1 user reported the free "demo" app worked, but then 2 others reported it didn't.
4: "Clear Faults" AFTER steps 2 & 3 above, with OBD or multiple key cycles.

(pic from my own perfectly-working 500e)
Some users say OBD sometimes needs clearing 2 or more separate control units, 2 or more times each, before it stays clear, but maybe they just didn't notice tiny on-screen instructions for special key-positions such as "stop", "mar" or "avv" required to clear some faults:

If you don't have OBD, codes will often clear with the key off for 3 minutes. Repeat if needed, up to 10 times, but usually ONCE works for me, & the most I've ever needed is 3 times, off for just 1.5min for the screen to go fully black (not just really dark grey), but other users report needing 3 min, 5-10 times.
5: Reboot via 12V disconnect AFTER steps 2 & 3 above, & after the key is off for 3-min without opening or closing either door or hatch. A 30-second 12V disconnect worked for me, but when that failed for other users, & so did 30 minutes, 30 hours worked. Ideally, disconnect the NEGATIVE, since it’s more robust, & it won’t short out the 10mm wrench (or even pliers, in a pinch) on any surrounding metal. Retighten it until it won't twist off of the post by hand.
6: Reboot via HV disconnect AFTER steps 2 & 3 above. If your car works, do NOT try this unless you have $50 AlfaOBD in case #3B is needed:
a) Open the hood & left door & don't open or close anything else* for the entire process, to avoid "wake up" signal.
b) Remove the key, wait 3+ minutes for "sleep" mode.
"Click to enlarge" version:

c) Remove the orange plug, disconnect 12V 30+ seconds, push the white part to open the black part 90º, to the center of the orange part, then replace the HV plug, then reconnect 12V.
IF that doesn't work, repeat #3B above.
Some users say that a different sequence is required, but it may just be that they didn't get it quite right the first time. There are at least 3 other sequences, but for ANY of them make SURE to first ALWAYS do steps A & B above, check car function after each one, & repeat #3B, before you continue:
c2) Disconnect HV 30+ seconds & reconnect. Disconnect 12V 30+ seconds & reconnect.
c3) Disconnect 12V, disconnect HV 30+ seconds & reconnect, connect 12V.
c4) Disconnect HV, disconnect 12V 30+ seconds, reconnect, wait 3 minutes, reconnect HV.
* I thought that only the left door woke it up, since it's the only one that awakens the HV systems (contactor clunk), HOWEVER the other door and even the hatch can awaken the 12V systems (instrument screen lights up).
7th edit 9/28/22: Copied 2 thru 6 straight off "dead 500e" post, but warning added to #6.
6th edit 9/25/22: #3A replaced jumpstarting with BM2
5th edit 9/23/22: #4 Onscreen fineprint, thanks to @jedwards1654
4th edit 9/3/22: #6 Press the white HV lock to open the black arm 90º, thanks to @rxd24
3rd edit 8/25/22: #6 Lock WIDE open before HV fuse insertion
2nd edit 8/22/22: #2B needs PAID version of AlfaOBD, & #6 can require #2B after
Edit 12/24/21: #2B "Contactor Glitch" added, thanks to @MDMTahiti & @witmannerik (for confirming it worked)
Credit for #6c2 to RatfinkHarley & BoggleMe on the other forum.