2012 JK with 85,000 miles. About two weeks ago it died while driving and would not start back up. It cranks but does not turn over. Here is what I have troubleshot and results:
- sprayed some starting fluid in and it starts for a couple seconds and dies.
- Fuel pump relay: measured voltage inside the fuse box at M25 fuse terminal. No voltage with the key in off. Battery voltage for ~2 seconds when the key is taken to run until the relay clicks and voltage goes away. Based on this i think the relay is good.
- Fuel pump: Made a jumper to plug into the fuse terminals in the fuse box. I applied power from the rear cigarette lighter (right 2 slots of M7) directly to M25. Could not hear the fuel pump running.
- Dropped the fuel tank and measured voltage at the 4 pin connector. Measured battery voltage across the #4 and #1 pins. Based on this I assumed the fuel pump was bad.
- Bought a new fuel pump, tested it inside a bucket of water and it worked fine. Hooked everything up and now the pump will not turn on either with the key in run or with power jumpered to it as described above.
- The fuel gauge is reading accurately with the new fuel pump installed so i am assuming that the 4 pin connector is made up properly.

Does anyone have any ideas or a schematic of the fuel pump circuit? I can’t think of anything that would be preventing the pump from running. Any help would be greatly appreciated!

 

Hi there! having the same issue on my 2012 JK did you ever find a solution?

 

I don’t know about jeep but other cars won’t power the pump unless the engine is running, This is to turn off the pump in the event of an accident.
GM looks for a tach signal and then turns on the pump, GM also pre-primes the fuel system by running for two sec so pressure is there to start.
Mazda looks for oil pressure to enable the pump.
I don’t know how Jeep does it, but I suspect whatever signal is used if one is, is missing.
Mazda and GM the ECU operates the pump.
This may help https://www.wranglerforum.com/thread...-time.2433156/