2015 Jeep Grand Cherokee No Power

Lesage Technician Dearborn Heights, Michigan Posted   Latest   Edited  
Discussion
Electrical
2015 Jeep Grand Cherokee Limited 3.6L (G ERB) 8-spd (845RE)—1C4RJFBG1FC815462
No Power

I've seen this vehicle start and run with all lights working but it would not move in Drive. Transmission shop shipped it back claiming it had no power. I confirmed that only prndl on shifter and off on push button are lit up with battery charger connected. PDC aka under-hood fuse box has power and some fuses light the test light. 

Now alldata shows that Run/Acc relays 1 & 2, Run relays 1 & 2, and Run/Start relay all are controlled by the BCM on pin 85. BCM gets power through fuses 10, 12, 14, and 23. With battery charger connected F23 is at 5.4V, F14 is at 0V, F12 is 5.4V, and F10 is 2.4V. All of these circuits are supposed to be hot at all times. One oddity is that F12 when connected to the same way as the other fuses shows reverse polarity -5.4V. I connected a test light to ground and to the P/S pump control module power wire after I disconnected the connector then i jumped pins 30 and 87 at the Run/Start relay base. Test light lit up, throttle body actuated and everything on the Run/Start relay circuit reacted. 

I'm calling a bad PDC because BCM is not being powered properly. Is there anything else I'm missing?

PS: not sure about the transmission model

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Albin Diagnostician
Leavenworth, Washington
Albin Default
 

You mention the battery charger being connected. What happens if the battery charger is removed? Where do you have power and where do you not have power? Test the vehicle in the condition it lives in.

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Lesage Technician
Dearborn Heights, Michigan
Lesage Default
 

Thanks Albin. With the charger disconnected and batt. voltage (11.3V) taken at jump starting points, F23 is at 4.8V, F14 is still a ghost voltage 0V, F12 is at 4.5V, and F10 is at 2V. Basically the same.

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Mike Mobile Technician
Charleston, South Carolina
Mike Default
 

Because of your voltage issues I am almost certain this isn't your issue but it's worth throwing out there. Whenever I run into odd symptoms in an FCA product of that year range the first thing I do is perform a restore vehicle configuration or PROXI alignment. I've seen vehicles do odd things when the configuration is lost.

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Lesage Technician
Dearborn Heights, Michigan
Lesage Default
 

Thanks. How are gonna do that without power?

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