friend has these codes on her Legacy sedan. i can't recall what kind it is...but i think it's a 2.5 liter. auto transmission. searched for those codes on here and didn't find anything. guys that read the code told her "Emissions Control System Sensor" and i saw them listed as "EVAP Pressure Sensor Range Problem" and "EVAP Pressure Sensor High Output".

those both have to do with the fuel tank pressure sensor. unless there is damage to the wiring going to it, or the pressure/vacuum lines going to it, the sensor itself has likely failed. not terribly hard to replace, but you've got to remove the gas tank (easier empty), and also access the wiring inside the quarter panel. good luck!

~Erik~

For 2.5L ('00obw):

 

DTC P0451 - EVAPORATIVE EMISSION CONTROL SYSTEM PRESSURE SENSOR RANGE/PERFORMANCE PROBLEM

DTC DETECTING CONDITION: Two consecutive driving cycles with fault

The service procedure has you check all the gas cap, fuel tank hoses, filler pipe, etc., and if those are good replace fuel tank pressure sensor.

 

DTC P0453 - EVAPORATIVE EMISSION CONTROL SYSTEM PRESSURE SENSOR HIGH INPUT

DTC DETECTING CONDITION: Immediately at fault recognition

The service procedure basically has you check all the connections for shorts/opens/etc, and if all those are good replace the fuel tank pressure sensor.

 

At least on this '00obw, it shows only a couple bolts/connectors to replace the fuel tank pressure sensor?

wow sounds like it could be a PITA. is there access through the trunk for this sensor like the fuel sender???

 

i have a 1997 impreza Subaru Factory Service Manual. would this fuel system, pressure sender be similar on a 1998 Legacy?

 

i'll start by replacing the gas cap and check for rust on the filler pipe then start looking into this pressure sender. that explains why i couldn't find any info, never heard of those failing before.