So here’s my post about the fun of troubleshooting remote starter issues with a 2015 Jeep Patriot – I hope this will eventually help other people!

I ran into the dreaded “beep once and not start” with our Patriot recently.  I checked the recommendations from the forums: full gas, all the doors closed, brand new battery in the car and remotes – none of that made a difference.  I purchased AlfaOBD and the recommended OBD to USB adapter.  This allowed me to pull the body codes from the ECU.  I pulled B1820 Hood Ajar Input Circuit High.

As it turns out (in my case, and apparently, most cases) this issue is caused by the hood latch switch failing.  The part in question is 68261145aa.  There are two connections to this part: Ground and Hood Ajar.  There are 3 possibly states for the Hood Ajar line: Hood Open (SHORT), Hood Closed(EOL Detected), B1820 (OPEN/HIGH).  The switch in the latch apparently contains a 1k ohm resistor that is used as an EOL (End of Line).  When this EOL fails (or the harness is unplugged/breaks) the Hood Ajar line will rise to a full 12v.  After 10 seconds a B1820 code will be raised by the TIPM.  This will block the remote start from operating.

To verify this failure mode:

• Use a screwdriver to force the hood latch mechanism into the “closed” state.
• Measure the pins of the Hood Ajar switch (NOTE: add photo here in edit) using a multi-meter set to OHMS.
  • If you read 1k ohms, then check the harness for damage
  • If you read “open” replace the latch mechanism

Please note: this switch can be bypassed by disconnecting the hood latch and pressing a 1k ohm 1/2w resistor into the connector.  I DO NOT recommend that, as this switch’s purpose is to prevent accidental activation of the remote start while someone is working in the engine bay!

This post will be updated as I manage to take photos and do the replacement of the latch in my vehicle.