How to Fix iPhone 13 Face ID Not Working

A video demonstrating iPhone 13 screen replacement was recently shared by Phone Repair Guru.Following the screen replacement procedure, users are reporting the appearance of an "Important Display Message" on their devices.Simultaneously, the functionality of Face ID is being rendered unavailable after the replacement.The iPhone 13's display design integrates the TrueDepth system components directly into the device's body, lacking a separate flood illuminator module.REWA LAB proposes that Face ID authentication data is stored on a chip present within the original screen assembly.
To test this theory, we will attempt to transfer the chip from the original screen to the replacement screen to potentially restore Face ID functionality.

• Begin by verifying the operational status of the iPhone 13's Face ID feature, confirming that the True Tone display functionality is also behaving as expected, and confirming successful Face ID setup and proper function.
• Proceed with disassembling the device and subsequently substitute the existing display assembly with a new, authentic component, ensuring the removal of the original screen.

• Using a hot air gun, carefully disconnect the sensor flex cable, maintaining a temperature of 100 degrees Celsius.Exercise caution during flex cable removal to prevent any physical harm.Secure the sensor flex cable to the replacement screen, then fasten the retaining screws.
• Complete the assembly by connecting the new screen and powering on the device to verify functionality.

A critical on-screen notification indicating a problem with the display is observed, accompanied by the inability to configure Face ID functionality and the loss of True Tone color calibration.The device's Face ID system is rendered unusable, preventing its setup or operation, coinciding with the absence of True Tone display adjustments.A diagnostic message surfaces on the screen, signaling a display issue and revealing that Face ID configuration has failed, while True Tone functionality is no longer active.

• As a subsequent step, attempt relocating the integrated circuit from the initial display panel onto the replacement display panel.
• To safeguard the display surface from abrasion during the repair process, adhere a protective layer to the screen's exterior.
• Employ a hot air rework station, setting the temperature to 100 degrees Celsius, to warm the display cable.Using a hot air gun, apply heat at a temperature of 100°C to the screen's flexible cable, then carefully detach it.For screen protection during this procedure, position a reballing template beneath the flexible cable to provide insulation.
• The flexible cable should be carefully lifted after applying heat with the hot air rework station.

• Secure the area with heat-resistant tape to prevent damage.
• Utilize a specialized tool to eliminate the dark adhesive surrounding the integrated circuit.Employ a Hot Air Gun for targeted heat application.Maintain a temperature of 240 degrees Celsius during the adhesive removal process.
• Chip extraction necessitates a temperature setting of 300 degrees Celsius and an airflow rate of 6 units.

• Utilize solder paste formulated for intermediate temperature applications.
• Thoroughly remove contaminants from the bonding pads using a Soldering Iron.Employ a Soldering Iron maintained at a temperature of 360 degrees Celsius, alongside solder wick, to facilitate the removal of excess solder.Continue the cleaning process of the bonding pads, employing a PCB Cleaner to ensure complete removal of residues.
• The bonding pads must be cleansed repeatedly to guarantee a clean surface for subsequent operations.

• Employing the identical procedure as before, detach the integrated circuit from the initial display panel.
• To ensure proper adhesion, eliminate residual solder from the chip's contact points on the original screen.
• Utilize "Solder Wick" to meticulously remove any remaining solder and black adhesive residue from the chip's bonding areas.Continue the cleaning process of the bonding pads, utilizing a PCB Cleaner to eliminate contaminants.Proceed with chip reballing by precisely positioning the reballing template.
• Distribute a uniform layer of middle-temperature Solder Paste across the stencil to prepare for component reflow.

• Following the creation of the solder ball connections, utilize a cleaning solvent designated as 'PCB cleaner' to eliminate residue.A 'Paste Flux' compound should be applied to the designated bonding areas on the replacement display's surface.Carefully position the integrated circuit from the original display to ensure precise alignment.
• Employ a 'Hot Air Gun' to reflow the solder, maintaining a temperature of 300 degrees Celsius.Once the flexible cable has reached ambient temperature, detach the high-temperature masking tape.The application of 'Paste Flux' facilitates the soldering process by promoting wetting and flow.
• Precise alignment of the integrated circuit is crucial for proper functionality of the replacement display.Reflowing the solder with a 'Hot Air Gun' at 300 °C ensures robust and reliable connections.Removal of the high-temperature tape should occur only after the flex cable has completely cooled to prevent damage.

• Establish a connection between the display assembly and the device's internal circuitry.
• Power up the mobile device; the anticipated "Important Display Message" should not appear.
• Facial recognition functionality is operational and can be configured without issue, indicating proper sensor function.The True Tone feature, which adjusts the display's color temperature to match ambient lighting, remains non-functional.Restoration of True Tone functionality is currently incomplete, suggesting a potential calibration or hardware fault.