Code p0722 I've changed the sensor now the code won't go away or reset

Try an oil and filter change. The 2 litre CDTi's are known for oil flow and oil pressure issues especially higher mileage models. The lack of oil flow can make the engine struggle.

If you have an OBD2 tool you should be able to reset the code. If the code is coming back then you either have a vacuum leak or a problem with the Mass air flow sensor.

MAP SENSOR will do this exact thing.... Some vehiles you have to clear the codes and allow the vehicle to RELEARN...

TPS (Throttle Position Sensor) that is failing will also do this same thing

Why would you be at a dealer with a 10 year old vehicle

Have extra money to throw away

How about a local repair shop

How is it you had work done & still
have any problems,what do these
shops do,half a job

no that is way to much. it is only 1 hour labor

If you have replaced the crank sensor and the code comes back, it may be a problem with the wiring harness or connector, or the plate the sensor reads.

check ATF level

If your ABS light is on, changing the brake (pads) won't fix the light.
There are several reasons for the ABS light to go on, and probably the most common is the connection to one of the four wheel speed sensors, or bad sensors. On most GMs, the sensor and wheel bearing are one assembly.
First, you need to get the error code read via the OBD2 plug. The dealer can do it of course. And many parts stores, such as AutoZone will scan for codes for free.
The code will give you a clue to the problem. Until the problem is fixed, the light can be reset, but it will turn back on almost right away.

Have you had the battery changed since you had the car. Have that checked for a full charge and no dead cells. Always have the air-conditioning completely off when starting the car. The starter takes a lot of amps to turn over and having the AC on doesn't help.

and another reason is the code didn't clear out completely. this tool can help you test the code.

maf sensor