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I2C Device Not Found

Arduino Microcontroller Board

Severity: Moderate

Source: OnlyErrorCodes.com — Every error code. One place.

Arduino I2C Device Not Found — How to Fix

What Does This Error Mean?

I2C device not found on Arduino means the scanner returns no addresses. The most common cause is SDA and SCL wires swapped, or the I2C bus missing pull-up resistors. Run the I2C scanner sketch and check your wiring against the device datasheet.

Affected Models

  • Arduino Uno
  • Arduino Nano
  • Arduino Mega 2560
  • Arduino Leonardo
  • Arduino Pro Mini
  • Arduino clones

Common Causes

  • SDA and SCL wires swapped at the device or the Arduino
  • Missing or too-weak pull-up resistors on the I2C bus
  • Device powered at 5V but Arduino I2C pins only tolerating 3.3V (or vice versa)
  • Wrong I2C address in the code — some modules have address solder pads
  • Multiple devices sharing the same I2C address causing a bus conflict

How to Fix It