A2251 820-01949-A 5.1V 0.24A on USB-C port after liquid damage

[vinaypundith]

So I've got this motherboard - 820-01949-A from an A2251 13" macbook pro. I am told the board previously had liquid damage (not told where on the board the spill was) - there are no visible signs, but it was cleaned about 2 years ago and stored since then. All four USB-C ports show 5.1V at 0.24A when I plug in a charger - all of them are steady at this reading, none of them are boot looping and none of them show a different voltage or current. I'm new to board repair, and kind of lost as to what to check or trace next.

I've taken the following readings:
PPBUS_G3H is 12.26 (From what I read, this means CALPE PMU fails to communicate with SMC - which is the T2 chip here? is it?)
PP1V8_SLPS2R is 1.8V (measured near both CD3217's on the side thats plugged in)

PP3V3_G3H_RTC is 3.33V
PP3V3_G3H is 3.38V
PP3V3_G3H_PMU_VDDMAIN is 3.32V

PP0V8_SLPS2R: 0.800V
PP3V_G3H_RTC: 3.00V
PP1V2_AWAKE: 1.2V

R8018 is physically missing from board - looks broken off. According to the schematic this is supposed to be a 1M resistor connecting PMU_XTAL1 and PMU_XTAL2. What are the PMU_XTAL lines and what is the function of the 1M resistor connecting them?


I2C_PMU_SCL diode mode reading is 0.525.
I2C_PMU_SDA diode mode reading is 0.504.

Any suggestions on what to test/check/trace next would be much appreciated!

 

[2informaticos]

R8018 is marked as "NOSTUFF" in schematic, so not even mounted.

Did you test with good battery, holding some charge?