# VAIS vacuum reservoir dead (what does it do?) Code P1800



## dra2650 (Oct 16, 2014)

My 2004 Maxima threw a P1800 code. The solenoid is working. Vacuum going in to the reservoir, but not coming out. I stuck the inlet and outlet lines together and the actuator pulled in and released at the appropriate rpms... or at least seems to. The reservoir is clogged or broken in some way (vacuum going in but none come out). Being a "closed" system, what does it do? Can I just connect the outlet line straight to the solenoid and bypass the reservoir? Or does the reservoir "vent" the vacuum in some special way when the solenoid shuts off the vacuum.
There is almost NOOO info about this part online and is hard to find this part for this 04, even on dealer parts sites.
Supposedly, it is #22370-7Y00A, but it "doesn't fit the '04" according to the local dealer's website.

Help, Please. System layout below, Thanks


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## rogoman (Dec 16, 2004)

There are diagnostic procedures in the FSM for testing the electrical components for the VAIS system. You can download a copy of the FSM for your vehicle from:




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2004 Nissan Maxima – Repair Manual - Emission Control System (Section EC) – 706 Pages – PDF






ownersmanuals2.com





The EC.PDF section is the one you need to read.


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## dra2650 (Oct 16, 2014)

Thanks. That was helpful. My diagram (how the car actually is) is routed differently than the service manual shows. The difference is the solenoid is before the tank on the car and the tank is first in the manual. If all components are functional this should not matter, but the manual's route would prevent a vacuum leak to the engine if the solenoid were to fail and get stuck half way. The tank adds vacuum leak protection (solenoid and 2 of the 3 vacuum lines). I think I am going to just take the tank out of the loop, replace all the lines, and call it a day.


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