Sim Card Detection Failure; Maintenance Process - Huawei P20 Maintenance Manual

4.2 SIM Card Detection Failure

4.2.1 Maintenance Process

SIM card detection
failure
Replace the SIM card
Test the SIM card
Fail
Replace the card tray
Test the SIM card
Fail
Visually
inspect the card
slot
No damage
Test GPIO_
SIMx_DET
Signal
detected
Test the
impedance of all
pins of the SIM
card holder
Pass
Test the
signals of all pins
of the SIM card
holder
Pass
Test the time
sequence
Pass
Software is faulty.
Try formatting the
phone
2019-6-25
EML-L29V100R001 Advanced Maintenance Manual V2.1
Pass
The original SIM
card is damaged
Pass
Replace the card tray
Damage
found
Replace the card slot
No
signal
Replace the
card holder
Fail
Check components
on related circuits
Fail
Fail
main chip using an X-ray
Pass
Huawei Confidential
Fail
Pass
Fail
Check the
machine
INTERNAL
Replace defective
components
Replace the main chip
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