void setup()
{
Wire.begin();

Serial.begin(9600);
while (!Serial); // Leonardo: wait for serial monitor
Serial.println("\nI2C Scanner");
}

void loop()
{
byte error, address;
int nDevices;

Serial.println("Scanning...");

nDevices = 0;
for(address = 1; address < 127; address++ )
{
// The i2c_scanner uses the return value of
// the Write.endTransmisstion to see if
// a device did acknowledge to the address.
Wire.beginTransmission(address);
error = Wire.endTransmission();

if (error == 0)
{
  Serial.print("I2C device found at address 0x");
  if (address<16) 
    Serial.print("0");
  Serial.print(address,HEX);
  Serial.println("  !");

  nDevices++;
}
else if (error==4) 
{
  Serial.print("Unknown error at address 0x");
  if (address<16) 
    Serial.print("0");
  Serial.println(address,HEX);
}    

}
if (nDevices == 0)
Serial.println("No I2C devices found\n");
else
Serial.println("done\n");

delay(5000); // wait 5 seconds for next scan
}

Serial monitor reports -

Scanning...
No I2C devices found

I think this is because its not looking at the correct pins.

How do I get this to work on the esp32?