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2009 F150 STX low battery voltage

Posted: Wed Sep 19, 2018 1:11 am
by BoomDog12
I am trying to read the modules in order to know where everything is located, but I keep getting a “battery voltage is low”message and can go no further. I have battery charger hooked up and the truck battery is fully charged. What battery is FORScan referring to? Help!

Re: 2009 F150 STX low battery voltage

Posted: Mon Sep 24, 2018 12:07 pm
by Juice
Check what battery voltage is being seen by the PCM with live data stream in Forscan. With the charger on engine off, you should be seeing 13v or higher in live data.

Re: 2009 F150 STX low battery voltage

Posted: Sun Sep 30, 2018 7:17 pm
by Majorbones73
I think it sounds like the Same problem, I had on my mondeo.
Nothing I tried would get it to read, so my only option, was to start the car!
Once it started running through the sequence, that’s when I turned the engine off.
Hope this helps ?

Re: 2009 F150 STX low battery voltage

Posted: Sun Sep 30, 2018 10:40 pm
by BoomDog12
I looked in the PCM and the only thing I could find was checking voltage from the ECU. It showed between 11.7 to 11.9 in voltage. I could start and let the truck run for a few minutes, turn off and would not get the error of low voltage. I was a little uneasy to use the WiFi dongle to write with so I returned the WiFi dongle for a USB dongle. Did not have the same problem I had with the WiFi one. Thanks for the help!!