Ok, new issue on a car I just replaced fuel rail on........car seems to run great, obd indicating no codes, all readiness monitors complete and green, battery reading 12v sitting still and 14v at control module when idling, but.........when first started car after fuel rail repair, dash showed "smart key low battery" message. So I put in fresh smart key battery. Now, the car cranks and starts just fine but touchscreen briefly displays "low battery, entertainment will turn off in 20 seconds if car not started" message, then goes away. Battery in this car is only 12 months old, terminals are clean, and it's strange this immediately happened after reconnecting all the harnesses related to fuel rail repair. Why would touchscreen say to start the car if the car is already running?

 

I had the same message. A battery at rest after being driven the day before should be 12.5v or there abouts. If your battery is 12v or less, it is not being charged all the way and/or it has a bad cell and can’t be charged. Test the battery with a Medtronic or similar. Check the battery counter in the car’s battery management system. Mine had never, had a new battery registered and therefore the battery management system had no idea it could charge my newer battery fully. After resetting the counter I have not seen the message.

 

Thanks for that helpful advice. This battery was dealer installed one year ago and I assume "registered", but how do I check the battery counter in the battery management system?

 

With an Autel or something running SDD. While you're there check to see if the system is expecting to see a flooded or an AGM 'cause the charging schemes are different. Charging scheme and battery type need to match.

 

So, the car sat a couple days because I needed the Pace to drag my trailer around. Got the message once I started driving the XF again. (Started just fine.) Got it a couple more times even though I drove it a bunch. Got it one time and it stayed on until I stopped and restarted the engine.

 

Yes keep driving as I also think it's the BMS getting use to the battery again after being unhooked. As you know this system discharges the battery to a certain percent then recharges it from there until it gets happy again.

You may not have any problem?
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