car reads low batt plz start in the past i unhooked the neg batt post and it cleared the problem . any time i change the obc it reappears , this time i unhooked the pos post , is their a difference in which post i unhook??

 

Shouldn’t matter which post. Do you still have the original battery? if so, it’s due to be replaced.

 

Sounds like whatever you're connecting to the OBC isn't closing the session correctly and is leaving modules in a "battery drain" state.

 

new batt my dealer replace the batt a year ago and the next day it showed low batt . i disconnect the neg post and it cleared the problem until i had the smog test then it appeared again about two days later . unhooked the neg post and problem disappeared . changed my program and it reappeared and will not clear

 

CHARGE THE BATTERY! Yes, in capital letters. New batteries are virtually never fully charged on installation and yours has probably never reached full charged. Your car has been trying to tell you that it is starved for voltage! Please consider mounting and using a good battery maintainer nota battery “charger”.

 

Just went through this while tuning my DSP. Battery was fully charged and still got the message. Did the disconnect too.

@santacruz11 Charging won't do it - you need to reset the BMS using a bi-directional OBD2 scanner like .

https://www.jaguarforums.com/forum/f...2/#post2859858

 

I have this issue every year when I get the smog inspection. Did not disconnect the negative terminal in time this year and the battery went completely dead. Had the car jumped, drove it and put it on a battery tender and it still discharged after that. After disconnecting the battery for a short time is was fine.