XPS 13 9370, fingerprint reader not connected

I’m writing this post in hopes that we can better diagnose finger print reader problems with more details than merely “It does not work.” It appears from some other forum posts that user posted solutions work for some and not others, thus indicating that we are not experiencing the same issues.

My configuration

• Dell XPS 13 9370
• I7 8550U
• 8gb ram
• 4k monitor
• 512gb ssd
• Windows 10 Pro (Version: 10.0.17134 Build: 17134)
• Bios version: 1.6.3
• Goodix driver version: 2.1.31.400
• Intel Software Guard Extensions Platform Software: 1.9.100.41172
• Bios setting: Intel Software Guard Extension – Intel SGX -> Software
• Still under warranty

History of device

The device has been serviced by a Dell technician a few times.

• Initially the power indicator LED to the left of the device not being lit even when fully charged.

Power LED not consistent brightness even at 100% charged

• Visit 1: Technician replaced the palm rest and the problem was not resolved.
• Technician then diagnosed that the plastic spacer on the system board with the LEDs are slightly bent and therefore light was not aligned with the palm rest holes.
• Another visit needed to be scheduled.
• Meanwhile, I found that speaker was broken, case not closed properly leaving a gap between the charging light and bottom case, and power button not giving tactile feedback thus the laptop cannot be turned on.

Shortly after technician leaves I notice this gap. Later I learn that it can be fixed by pressing together the two halves.

• Visit 2: The system board was replaced.
• Visit 3: Technician replaced speakers.
• The palm rest is found to have few broken fins on the exhaust/intake under the monitor.

• Visit 4: Technician replaced the palm rest.
• After it's done, I test the machine and find that the touch pad did not give tactile click while the screws were on tightly. The technician fixed it by not tightening screws too tightly.
• Technician was made aware of the problem with finger print reader and was given a number to contact their software department.
• Calls software department
• Was told to reinstall windows
• Reinstalled windows
• Finger print reader still doesn’t work.

Observations

• Device manager fails to detect the finger print reader. It says the finger print reader is not connected to computer. See picture

Device Manager does not show fingerprint reader as connected

• I know that it is connected because it sometimes work and when asking the technician about the connector, it appears that it is in properly.
• On the “Sign-in Options page” the fingerprint login does not appear like some other users. (I do have pin sign-in enabled.)

Another Users problem shows the finger print option under windows helloMine does not show fingerprint option

• The fingerprint works intermittently. Sometimes it does not work even when I shutdown and turn on via power button. Sometimes it fail to work after it goes into deep sleep. There is no message saying fingerprint is not recognized. Likely due to device manager simply do not detect that a finger print is plugged in.
• The Goodix Finger print reader driver cannot be reinstalled since it returns a finger print reader cannot be detected. The solution of uninstalling the Goodix driver, install Intel Software Guard Extensions Platform Software and then reinstall Goodix driver has not been attempted since it may be impossible to reinstall with device manager not detecting the fingerprint reader.
• Cannot install Goodix driver as fingerprint device not detected
• If I remember correctly, Dell SupportAssist has the capabilities to test the finger print reader individually, but that option disappears when the finger print reader cannot be detected to be installed.

No option of testing finger print reader right now since finger print reader is not detected to be connected.

Speculation/ Theory

I speculate it may be similar to the way iPhone Touch ID stops working with home button replacement. Certain verification between the fingerprint sensor and the system board's chips may fail as my system board has been replaced. I cannot explain why it works sometimes and does not at other times.

The most relevant troubleshooting link I can find which lists replacement of motherboard as a potential issue is here but it is not updated to describe any fix associated with the newer model of laptops.To quote the link. “If any hardware components are installed/swapped/removed (including Motherboard, Fringerprint Reader, Bios Battery), software changed, drivers re-installed, BIOS reset, then Fingerprint data can be affected and this can all be rectified in troubleshooting with no hardware required”

“A good fix for fingerprint reader issues is to always re-flash the Control Vault.”
However, I do not believe that the XPS 13 9370 uses control vault nor control point nor Dell Data Protection|Security Tools since these drivers cannot be found under the driver tab of 9370. 

In the installation guide for finger print reader it states that it uses Dell Data Protection|Security Tools (DDP|ST) but the data protection in question cannot be found on 9370’s driver page.
I think the problem at hand may be similar to the troubleshooting guide above but I do not understand the exact security mechanism for the 9370. A system similar to Control Vault/ Control Point/ DDP|ST may need to be reinstalled with a new system board but I cannot find the relevant drivers.

I hope some of you who understands the requirement/ mechanism of Windows Hello can assist with fixing the finger print reader rather than a series of copy and paste links which aren’t directly relevant to the 9370. I do believe that a system similar to Control Vault need to be re-flashed but I don’t know what system is used on 9370. Will clearing TPM fix the problem? Is the TPM chip located on system board?