820-00840-A (2017 13" MBP) PPBUS_G3H at 1.1V, USB at 20V but 0.04A flowing, No Power or Charge

[2informaticos]

Ball F2/U7000 isn't EN_VR1?

Both USB-C ports must have the same behavior.
If not, you have a problem on USB-C area; need to find the culprit.
Please don't make "cardinal refferences" (lef/right, front/rear, up/down); post position component on the schematic/boardview.
Also use schematic instead of boardview, when you mention component pins (especially for BGA chips).

NEVER check board in diode mode, or ohm scale with charger, or battery connected!!!

Reffering to U3100/200, let us know the actual behavior of each port.
Compare diode mode readings on the 4 LDOS of both CD3215 chips.

 

[vinaypundith]

Found EN_VR1, as you said it's on the schematic. My boardview has it labeled as "PM_EN_P3V3_G3H". Voltage: 3.39V
The two USB-C port certainly do NOT have the same behavior. One does not even light up my power meter, and board voltages are very low (compared with what I've been posting here from the other port)

The working port is the one right next to the CD3215's, and the non-working one is right next to component L2950.

Port A (to U3100) is not functional at all (power meter only blinks on every few seconds, 0.3 or no volts at all test points that you mentioned.
Port B (to U3200) is partially functional, giving the voltages I have mentioned so far on all the test points you mentioned. 0.07-0.08A current flow as measured by USB-C power meter.
Machine does not power on on either port.

LDO readings are as follows:
U3200 (with cable connected to corresponding port):
LDO_3V3 (pin G1, PP3V3_UPC_XB_LDO): 3.32V
LDO_1V8A (pin K1, PP1V8_UPC_XB_LDOA): 1.79V
LDO_1V8D (pin A2, PP1V8_UPC_XB_LDOD): 1.78V
LDO_BMS (pin E1, PP1V1_UPC_XB_LDO_BMC): 1.11V
(All voltages are zero with USB-C connected to other - U3100 - port. Expected?)

U3100 (with cable connected to corresponding port: ALL 4 LDO voltages are zero volts.

Can an issue with U3100's circuit cause U3200's circuit also to not work?

 

[2informaticos]

SMC needs to talk with both U3100/200 chips.

"Compare diode mode readings on the 4 LDOs of both CD3215 chips."
???

Check diode mode to ground on CC1/2 pins of U3100.
Also inspect the terminals of the non-working USB-C port (possibly corrosion).
And test both ports in both connection ways; 4 combinations in total.