Samsung S21 Ultra Charging Paused: Temperature Jumper Solution

 Is your Samsung Galaxy S21 Ultra showing a "Charging paused: Battery temperature too low" or "Battery temperature too high" error? This common issue often prevents the device from charging even when the battery and cable are perfectly fine.

While this can sometimes be a software glitch, it is frequently caused by a hardware failure in the thermistor circuit on the sub-board or the main PCB. If replacing the charging port flex doesn't work, a jumper solution is the next professional step.

Why Does This Error Occur?

The S21 Ultra uses thermistors (resistors that change resistance with temperature) to monitor the heat of the phone. If the line connecting these sensors to the Power Management IC (PMIC) is broken or a component is corroded:

1. The CPU receives an incorrect voltage reading.

2. The system triggers a safety shutdown of the charging process.

3. The "Temperature Error" icon appears on the screen.

The Jumper Solution (Hardware Fix)

The image provided illustrates a bypass jumper. This method involves connecting a thin copper jumper wire from a specific test point or component to the signal line to restore the correct reference voltage.

Steps to Perform the Repair:

1. Disassemble the Device: Carefully remove the back glass and the wireless charging coil.

2. Identify the Area: Locate the section of the PCB near the FPC connector as shown in the microscopic view above.

3. Clean the Circuit: Use Iso-Propyl Alcohol (IPA) to clean any corrosion around the capacitors and resistors marked by the red arrows.

4. Apply the Jumper: * Using a fine-tip soldering iron, connect the jumper wire from the thermistor output point directly to the stable line indicated in the diagram.

   • Ensure the wire does not touch any surrounding ground (GND) points to avoid a short circuit.

5. Test: Plug in the charger before reassembling the full housing to ensure the temperature warning has disappeared.

Image Credit : Habu Tech

Note: This is a professional repair. If you are not experienced with micro-soldering, please seek help from a specialist, as incorrect jumpers can permanently damage the PMIC.

Conclusion

Hardware jumpers are a life-saver when replacement parts are unavailable or when the break is deep within the PCB layers. By following the Samsung S21 Ultra Jumper Ways shown above, you can successfully bypass the temperature sensing error and restore fast charging.