P0121 fault code
 

Hi,
I have a 2001 volvo s60 2.4T and my engine management light has been coming on. About a month ago there was a fault code for MAF so replaced that and it has been going ok till last week when the light came on again. The code that came up was P0121: TPS/Pedal position sensor A CKT range/perf. It was maybe hunting a bit but no other problems.
Any idea what might be causing this? I did wonder about cleaning the throttle body as i have heard they cause problems. If you think that might cure it what is the best way to remove it as i see it is under the inlet manifold.
Thanks in advance!!