Check all your grounds
It means your sensor heater in Sensor 1 or Bank 1 is malfunctioning. Get it replaced.
No, the abs is separate from the diagnostic plug fuse. If a sensor has failed, it will need replaced.
Have you replaced your air filter lately? If not, try that, reset the computer by unplugging the battery and see if it clears the code.
You need to get the temperature sensor repaired or, more likely, replaced.
you need an on board diagnostic scaner
IF IT'S A 3800, MAKE SURE THE O RINGS ARE ON THE PCV, AN EASY CHECK IS TO PLACE YOUR HAND OVER THE OIL FILL WITH THE ENGINE RUNNING, IF IT TRIES TO SUCK YOUR HAND INTO THE VALVE COVER THERE'S LIKELY AN O RING MISSING FROM THE PCV. THIS IS ONLY COMMON ON 3800'S.
What did the diagnostic code tell you before you replaced the EGR valve? You should not have replaced the EGR valve unless you have already run a diagnostic code otherwise you probably just wasted money. Oxygen sensors are a more common problem, especially since they routinely wear out. Also, map sensor, throttle position sensor, crankshaft position sensor... and a whole lot more, can cause a check engine light to come on. Don't guess; run a diagnostic code and figure out what the computer is detecting. Then replace ONLY what the computer indicates has failed.
If you are reading a code with the description "ambient temp. sensor open" that means that the sensor or the wiring to the sensor is open or broken. The sensor will have to be replaced or the wiring to the sensor repaired. Have it troubleshot prior to just throwing parts at it.
Be careful there is a temperature coolant switch mounted next to the thermostat housing. I thought this was the sensor and replaced it by mistake. There is another sensor.
This is referring to the first Oxygen sensor, located on the exhaust manifold. It either indicates a short in the wiring or the sensor needs to be replaced altogether.
This code is for the transmission The Direct clutch speed sensor. Have it tested most likely it has to be replaced. Had the same problem myself and managed to fix it by replacing the sensor.
Your valve timing is off The o2 sensor is not reading properly causing the system to go very lean.