check engine light is burning
 

hi, my car ( DIESEL SAAB 9.3 SE 5D 2.2 TID) is 19 years old and has 336000 kilometers. My question: the check engine light is burning, not all the time, but it comes up after driving about 20 kilometers (not always though). I went to the garage and they told me it is to do with codes P0403 and P1127. It would cost me about 800 euros to have it repaired. I don't think the car is worth spending so much money on. My question: is it dangerous to drive with this fault and what would happen if i don't have it repaired? many thanks for your help.