Cannot find PEM/FCU in 2004 XC90 2.5t AWD

[ggleavitt]

Yeah, you maybe don't have them on your vehicle. On the other hand, folks are right- you should not be coding a P0089 (Volvo ECM-280x, 290x) FPS code you don't have an FPS and PEM. MY05 is key, aligns with when the newer CEM gets put in and the revised DTC codes show up.

DECOS (Demand Controlled Fuel Supply) is the combination of FPS, PEM, ECM and Pump working together to provide needed fuel pressure as required. If your vehicle does not have DECOS (I supect most if not all before 2005 but there are clearly some exceptions noted) then you won't have them in place.

I had a look at a 2004 EWD, only the no-DECOS pump (6/31) is shown on the Engine Management page, pump has a direct connection from relay 2/23 on the CEM.

A 2005 copy of the EWD also notes 6/33 but it's bracketed between the lines for the DECOS pump (6/31). The 6/31 pump gets variable speed control (PWM) from the PEM via the ECM which reads the FPS for pressure and temperature feedback.

There are a few different part numbers for the pump depending on tank size and chassis number (last 6 of VIN). I did indeed find an odd PN break for my own vehicle (135488) so best is to ask someone with Volvo service access to run your VIN and see what you have installed.

Good luck with your repair.

040420- Edit for DTC add, typo.