if this is a 2010 model unit it will have the Woodward Tier 3 fuel system. this unit has a Bosch electronic throttle assembly that is controlled by the SECM and if it has a throttle related code the accelerator will not respond.

you need to check and see if the unit has any fault codes.

turn the key to the on position and depress the accelerator 3 times fully and wait for the Engine Light to start flashing. the first code will be a 2 digit code and it will be 12 after the 12 the codes are 3 digits and and the end of the fault list you will get anothe 12 and the cycle will start over again.

also check the harness connection at the electronic throttle and at the accelerator assembly and match sure they are clean and tight.