P0090 / P0087

just wondering if anyone has had the 2 codes as i have and managed to fix what the problem was, ive changed the sensor on the injector rail and also changed the high pressure fuel pump on top of the engine but still getting the same codes coming back

any help be nice as its burning my head out car being of only 19000 miles and in limp mode

2013 micra DIG-S

P0090 - Fuel Pressure Regulator 1 Control Circuit Open
P0087 - Fuel Rail/System Pressure

Whilst I am no mechanic, thinking about this logically, not all error codes point to the exact problem and could be the result of something earlier in the chain, rather than itself. Some of this is just me rambling on, but might be some food for thought.

Lets break down the system into its parts... reading the service manual...

1. Fuel tank low pressure (LP) pump. The assembly also contains a filter of some sort
2. Fuel line from tank pump assy to engine
3. The from tank fuel line then feeds into the high pressure fuel pump (HPFP)
4. HPFP then feeds into the fuel rail and then into the injectors
5. The fuel rail contains a fuel pressure sensor, and this is the first sensor I see mentioned within the service manual
6. It appears to me that this is a 'dead head' system as I see no reference to a return line

I see no reference to a regulator, so I would assume that I'm either missing something, the car does not have one, its integral into one of the fuel pumps, or there i modulation going on. It seems some other makes, the regulator is within the HPFP but the diagram does not show a 3rd line, just a supply and to fuel rail line.

The pressure sensor is 'last' in the chain before the injectors, so there is a whole heap of stuff 'before' it that could be wrong. However first, are you able to get reading from the pressure sensor? It could be that the sensor is fine but the wiring maybe bad somewhere?

If reading can be made, does it confirm that there is low pressure within the rail? I have no idea what is a good/bad reading so some digging is needed

If its low pressure, what could cause it? There are 2 pumps in this and I see you have changed one. However the low pressure side might not be supplying enough fuel to the high HPFP. Could the pump be bad, could the filter be blocked, could there be a blocked or damaged fuel line?

A 2013 car with only 19,000 files is quite low so it seen more than fair share of idle time. If its been sat around for a long time with fuel in the tank, then fuel can turn bad and clog things up.

How long have you had the car? Was it running and driving fine before the error codes? Any changes or oddness about the car just before the error codes appear? Did the car loose power, or cough/splutter just before the error codes...?
sorry for the delay, i found the problem it was a break in the wiring, painful, my car has no cruise control fitted on the steering wheel, you think if i got a steering wheel with the controls on it might work if programmed or what ever it is they do with there laptops these days
Where was the wiring broken? Might help if it becomes a common fault point :)

As for adding/removing features - I dare say it is possible. On my Megane RS, I have been able make a few changes using a program called DDT4ALL. There is a Micra listed within the database I use, however not sure which model its refers to however.