Vehicle going into limp mode.

4WD light comes ON and vehicle goes into limp mode. Followed testing procedures off Nissan workshop manual.

This occurred one day after head replaced. Replaced head assembly due to coolant loss.
WHAT REPAIRED:
Cylinder head, timing chain, tensioner and accelerator pedal.
Replaced, suction control valve but found no different so it was refitted.
Road tested and all good. Customer picked up vehicle and returned the next day with vehicle in limp mode.