820-01521 Battery not detected / SMC issue

[ThisIsWes:AASP]

Very clean machine/ board that I received from a local shop I do repairs for.
Customer left untouched in their truck for a while and when they attempted to use again it was dead. Shop removed board and inspected. Apparently, when they reassembled it would now turn on but no battery detected.
Diag shows PPT001 - No battery detected & PFM006 - May be an issue with SMC

Visually no issues with the board. No LED light. If it was just no battery detected I would assume dead battery but since SMC is mentioned I'm wondering if its something else. Also, I don't have another battery to test with at the moment and would like to avoid purchasing if not necessary.

When checking the battery itself I get 0v on the plug. following things back a bit I'm getting...
Main -/+ connections: 4.1v
1st mosfet source: 4.1v
drain: 3.85v
2nd mosfet source: 3.85v
drain: 0v
Do these batteries not supply voltage until they talk to the board? Does anyone have one they can compare values against?

PPVBAT_G3H_CONN: Alternates between 12.61v and 0.164v every 5 seconds with and without batt connected.
PPBUS_G3H: 12.61 constant

 

[2informaticos]

You should try known good battery.
"1st mosfet... 2nd mosfet", please use schematic!

Battery will not deliver any voltage, untill SYS_DETECT_L is pulled down; through R6950, or Q6955 (depends which present).

 

[ThisIsWes:AASP]

Don't have schematic for battery board... Do you?

Any other options before good battery?
Anyone have a machine they can remove the battery on and run diag to see if they get the same results?

 

[ThisIsWes:AASP]

Swapped out the battery and all is good.