Arduino Zero pin D4 not functioning as a Digital output

hi there.
maybe i am been slightly dense but i am unable to do a simple digitalWrite to pin D4.

my setup is as follows

pinMode(4,OUTPUT);
digitalWrite(4,HIGH);

this doesn't take the pin into a high state.
any suggestions?

ok i have solved the issue.
based on the variant.cpp file

PA14 ( which is defined as D4 in the schematics) is actually D2 )

This seems ok on my board:

void setup() {
  pinMode(4, OUTPUT);
}

void loop() {
  digitalWrite(4, HIGH);
  delay(1000);
  digitalWrite(4, LOW);
  delay(1000);
}

You probably have an Arduino.org M0 / M0+ board. It is a known difference between the Zero and the M0 : D2 and D4 are switched.