821-3115 palm rest sensor

[rlowe215]

Im back with a 821-3115 board.

No sign of water damage.

Fans spinning at full speed.

Test in ASD EFI shows error in:
Sensor - Temperature (Ts0P) Palm rest

Test in ASD OS shows error in:
Thermal Interface - Processor Error 255 heatsink
Temperature (Ts0P) Palm rest Error 13005 SMC can not read sensor
Temperature (Ts0p) Palm rest error 1 Unable to read sensor


Done so far:
Tested new trackpad and new trackpad cable
Disconnected everything from card accept keyboard and trackpad
Checked R5270/R5271
Checked pin 17 and 19 on J5800 shows 3.3V
Checked all pins on J5800 for short

What to do next?

 

[dukefawks]

Diode mode on I2C_TPAD_SDA and SCL. The iSight cable from the LCD can also cause an issue on this bus.

 

[rlowe215]

scl 0.519v
sda 0.445v

already tested without iSight cable attached without any result

 

[dukefawks]

Too much difference. Remove R5923/22 and check again. After that there is only one thing left on this bus and that is the SMC.
I assume you inspected trackpad connector/iSight connector and SCM area carefully for liquid/corrosion.

 

[rlowe215]

WIth R5923/22 remowed I have some new values
scl 0.710V
sda 0.646V

 

[dukefawks]

Fan still high? If so then it is probably a dead SMC.