The connector for the accelerator is in the passenger footwell on a Right Hand Drive C3 because the loom is an adaption of a LHD design

This connector is only found on the RHD C3 and can go high resistance to give P2101 fault code.
For S2000PM1 as fitted to TU3 engine in Citroen C3, check for harness problems. It may be necessary to replace the multi connector on the motorised throttle unit and delete the connector under the glove box, where the manufacturer has adapted from left hand drive.
The advice is to 'delete the connector' and these images show the connector to be deleted and what the wiring in the passenger footwell looks like after deletion.
The adhesive lined heat shrinkable sleeving used is available here.