2011 Qx 56 Fuel / Rail System Pressure - Too High

[jordan30107]

I have a 2011 QX56 with 186,000 miles. recently had CEL with P0087 and P0090 codes displayed. Replaced the HPFP lifter and it was obviously the issue as it was worn completely through on the bottom. Following reassembly I cleared the codes and tested the vehcile. Vehicle drives and operated correctly however not there is a P0088 code that has came up. I definately could see the HPFP creating the previous codes as it was functioning properly however the swap went perfenct and no issues. What would cause a Fuel Rail System Pressure - Too high code to occur?

 

[marctronixx]

some of my opinions.

it seems you did the work and you are fairly comfy doing it, so i would go back and check your work. visibly inspect the areas you took parts off and verify there are no loose/frayed wires or have disconnected harness.

Possible causes
– Faulty fuel pump
– Blocked fuel filter
– Faulty fuel pressure sensor
– Fuel pressure sensor harness is open or shorted
– Fuel pressure sensor electrical circuit poor connection
– Faulty Fuel injector

there could be a sensor that has failed or something is kinked along in the system, causing an open circuit and thus throwing a code.

these codes are general codes and arent specific to nissan, so sometimes you have to read between the lines.
you said your car drives fine? i did a cursory search on the code and some symptoms associated with the codes you mentioned are poor performance/stalling and dark smoke. again this is generic and may not happen, but i would think you would see some difference in performance on some level with this error.