Odd Fuel Pressure Issue - 2005 XC70

[jtb123]

Hello. I've been having an issue with my '05 XC70 where it, occasionally, struggles to start (but runs just fine once it gets going). I have a returning 2900 fuel pressure code and a P0089 regulator code. I'm not familiar with these cars at all, so I did all the basics - new fuel pump, fuel filter, and fuel pressure sensor on the rail. No resolution.

So I read about the PEM failures on this model, and replaced that thing - no resolution there. Today, we looked at the rail pressure with a gauge and compared to the pressure sensor and found the sensor is over-reporting consistently by 12psi. I pulled the PEM while running, let the pressure go down to 0psi and stall the engine, and the sensor pressure stopped at just over 12psi.

The sensor is already new, so I'm not suspicious of its function since the problem existed before and after its replacement. I suspected the pigtail connector for the sensor might be garbage, so I crimped in a new one and...the over-reporting increased from 12psi to 15psi. So, on the one hand it's nice to see the circuit affect the reported pressure from the sensor because it feels like the wiring further down the line may be the issue, but on the other hand...I am confused still.

Has anyone experienced anything like this?

[chrism]

Did you replace the sensor with the proper color Bosch sensor? They come in two colors, black and gray. One color is for turbo engines and the other color for non turbos, although I don’t recall off the top of my head which color is for which engine.

[jtb123]

I went with a gray bosch one, my engine is turbocharged. That was the OEM choice that resolved to my VIN through worldpac, so I just presumed it was correct...but worldpac has been wrong before..

Regardless, the issue was the same before the sensor replacement and afterward so I'm operating on the assumption that it's working the same as before. I'll double check that tomorrow though.