My 2009 vw passat 2.0 turbo has problems sputters knocks wont stay running i cant drive it thought it was maf sensor so i change it still has problems when i drove it before it would slow down speed on highway and would hardly go

SOURCE: Road speed sensor

So the diagnostic code says the speed sensor is bad in the transmission? Make sure all the wires are tight to the transmission and in good shape. If they are you probably need to replace the sensor. If the transmission controller doesn't get the correct speed values it would cause some problems shifting. Wiring to a transmission can cause faults since the wires are subjected to heat and vibration. If you can't find any problems with the wiring or the wiring connectors it just might be the sensor is bad (stuff fails).
I do have to say that I am not sure what G-68 means. The diagnostic codes are usually five digit numbers with maybe a letter.

SOURCE: How to replace ABS Sensor

They're a pain because they press into the hub. Some of them have a retaining bolt, others don't. The problem is that heat in the hub, from rolling friction in the wheel bearing and brake system heat transfer causes them to seize in place. The only way I've been able to remove them is to remove the end axle bolt that holds the axle in place, pivot the upright to gain access to the inside of the upright from behind, and tap the sensor out. You have to be careful not to damage it, and it helps a lot to spray some PB Blaster or penetrating oil in there to help loosen things up. If you try to pry or lever it out from the wire end of the sensor, you WILL destroy it.

SOURCE: 2003 VW Passat "Oil Press, Turn Off Engine" and "STOP" Light

I would check the oil pressure sensor and the oil pump itself. You can take the sensor out and use a mechanical gauge to check the oil pressure. If the oil pressure is within specs, you need a new sensor, if not, you need a new pump.

SOURCE: i have a 2000 vw passat wagon 1.8 turbo wagon

mass meter is going out and the flashes mean the car is misfirng probably the coils

SOURCE: vw golf tdi turbo problems

check the turbo hoses, they are renound for dry cracking, very hard to see at first glance