307 hdi limp mode reset?

a friends car was in limp mode and the eml was on, when i scanned it i found a code for low fuel pressure, the problem seemed to be a blocked fuel filter so we replaced with a new one and reset the code. also before we replaced it the fuel primer was under some sort of vacume! but now all seems fine and no codes have came back up the car is still in limp mode. is there a way to reset the limp mode??? cheers