Fault code diagnosis needed please

Hi,

My Fabia estate with a 1.4 16v BBZ engine from 2005 has starting to display fault codes. 
The car runs fine and the codes can be cleared but the first one has been seen a number of times, maybe a month apart. 

No obvious faults looking under the bonnet. I always run it on 99RON and the car has done nearly 120K miles. 
 

1. 17750 (P1142)

2. 17961 (P1153)

This 2nd code has only been seen once and it happened on Wednesday as my wife was driving through Warwick. She has never driven the car before so no idea if there were any symptoms other than a light popping up on the dash. 
She carried on to Oxford then returned home on the M40 later on. Apparently the dash light was still on when she set off to come home but when I started the car this morning no dash light but the 2nd fault had been logged when I scanned with my very basic tool. 
 

Searching the internet gives a few fault options but for any of you that has experienced the same faults what is/are the exact problem(s) and how to fix?

Thank you for any assistance.