update,
so far pullups changed to 9.0 Kohm, on both lines. Even with the one device on Bus, in serial monitor it shows full bus of devices. Even if I remove the i2c connection wires, it still shows full bus on devices.
Can it be related to i2s scanner program itself?
I found several ones, the one I am using is the following:
#include <Wire.h>
void setup()
{
Wire.begin();
Serial.begin(9600);
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
// Wire.endTransmission to see if
// a device acknowledged 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
}