Identifying SDA and SCL wires in I2C device
From the comments: Problem found - use the correct datasheet, this one for the analog output GP2Y0E02A and this for the I2C output GP2Y0E02B.

From the GP2Y0E02B datasheet, here is the pinout of the 4-way connector, showing SDA (pin 3) and SCL (pin 4) (as Bence Kaulics kindly explained in earlier comments). I have marked pin 1, as the drawing is quite blurry: