Toyota Hiace 2003 D4D Throwing On Engine Management Light

[classicpartsni]

hi all,i have a 2003 toyota hiace 2.5td d4d that is putting on the engine management light.a friend ran a dianogistics on it and it is showing up codes P0190(fuel rail sensor circuit)and P1226(excessive fuel pressure leakage)..i purchased the van a few months ago and had to change one injector due to someone before me breaking off the electrical plug..the van went well for around 1400 miles after fittment and then one morning it put the engine light on..i pushed the priming button at the filter head a few times and the van started up and went for another 200 miles before the light come on again.this happened a few more times and each time when i primed it up again the van went dead on.i assumed it was the diaphram in the priming pump and fitted a new pump but the problem is still there though it seems worse as it won't drive for any more than a mile.i am aware of compensation codes that have to be programed into the ecu if any injectors are changed though i couldn't find any code where it is supposed to be(on top of injector)and therefore never done this.i'm not certain though i think this doesn't have to be done on this van.has anyone any ideas of where the problem lies,or has anyone had these codes showing before.. if so what were the symptons before i start stripping to investigate..thanks..