MacBook Pro A1502 Battery not recognized repair

Problem description
Problem with MacBook Pro A1502 2015-2016 that is not recognizing the battery.

Symptoms

 * MacBook not recognizing the battery

Solution
First, try a known good battery.

If it doesn't work, check PPBUS_G3H. If it is 12.23 V, the SMC is not communicating with the battery on its data line, either because the SMC is bad, or because the pullup resistors on the data line are bad. On rare occasion U7100 can pull down the data lines. There is a shared data line between the battery, SMC, and ISL6259 (U7100). If PPBUS_G3H is 12.56 V, then you probably have a bad battery.