reset check engine light

hello
how do i reset this check engine light :?: :?:

the disco starts and runs, however when i press the throttle i can not get her to rev up :?: :?:

the landy moves under tick over but no revs :?: :?:

its a 1996 Discovery 300tdi ES Auto

any help would be be appreciated

becks

having replaced the damage loom a few days ago by cutting and splicing in a new section, all joints where soldered, today i stripped back the loom and found a broken wire that went to the accelerator potentiometer, reterminated and HEY PRESTO the check engine light went out.

took the disco for a test run and everything working as it was

its a good feeling getting everything sorted, imagine all this down to a blown exhaust manifold gasket