UK Ford Repair Questions? Ask a Mechanic for Answers ASAP
Hi there hope i can be of assistance,
Ok the p1554 is an injector fault code, cylinder 4
The P1664 fault code is for the injection pump.
If this is a common rail, have the number 4 injector removed and tested.
If this is not common rail, then have the timing chain checked> if this is ok, then its likely to be the injection pump which has failed.