My Front o2 sensor has gone bad. I can order one online and have my mechanic install it for a lot cheaper then if he buys the sensor. I want to buy a Bosch O2 front sensor for my 1999 Volvo V70 AWD with Turbo. Does anyone know what the Bosch part number is. I have checked and there are many parts. I'm not sure which part number is for the back and which is for the Front sensor. Anyone who could help, I would really appreciate it.