Trc/vsc And Engine Light On At The Same Time

[Cayenne]

I just had the vehicle serviced at 60000 miles (verso 2.2 d4d 58 plate) and within 100 miles the above mentioned lights all appeared on the display driving at about 30 to 40 mph.

I mainly drive in town and not long journeys avg 36-39 mpg.

Having researched the internet I found that if you pump the throttle five times with ignition off it may clear the problem. I did this and it worked!!!!

I then drove the car to work (25 miles motorway) and no lights or problems. Avg mpg 44-45.

What exactly does pumping the throttle do??