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Discussion Starter · #1 ·
So I’ve been hunting this cause of my ‘02 9-3 Vert’s P0455 CEL and I’m stuck

I checked the purge valve, it looks pretty new actually, and it holds vacuum when no power is applied. Apply power and it opens properly. With the car running there is vacuum out of the bottom port. So I don’t think it’s that.

I put on a new Orio/SAAB gas cap.

I changed the rubber hoses including the one that attaches to the back of the throttle body, they had small cracks but nothing that went all the way through.

I also changed the canister close valve (in the wheel well) but I think the original one was okay, actually.

With Tech 2 I commanded the canister close valve closed, and when I pulled vacuum with my MityVac on the purge connection on the canister, it held vacuum!! So I’m thinking that there’s probably no leaks with the canister, the fuel tank, or the hose going to the canister close valve.

Also, I know the car got a new fuel pump about a year before I got it, so I checked the tightness of the locking ring, and found it to be at the proper torque setting (55 lb-ft).

Is it possible that the charcoal canister is clogged? When I pulled off the hose that goes from the canister to the tank, there was a little gasoline that came out.

When the car does an EVAP integrity test, it goes down to -0.272 kPa, sometimes -0.300 kPa if it’s cold out. But from what I understand, it needs to get to -0.600 kPa within 23 seconds, or else it’s flagged as a P0455.

My hypothesis is that the charcoal canister is clogged up, and so the pressure can’t go down quickly enough to meet the criteria for.

Here’s a video showing the car testing itself after a cold start.

The second video is after a “forced” test via Tech 2, engine was hot.


 

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0455 is the generic code for an evap leak (not even large, just a leak) set by the tank.

It being the purge valve is more Asian. Normally with GM products (and yeah I can see that Russian person coming even saying that..), the Fuel Tank Pressure sensor is the culprit IF it isn't actually a leak. I sincerly doubt Saab did anything but use GM's bit for something so mundane.

I'd see if taking the cap on and off makes any real difference in the Fuel Tank Preassure reading... They tend to hang out at about 1.5 when wide open so 2-3 indicates a pretty big leak. But it's sensative to .2 so if it doesn't move when you take the cap off/ put it on I would replace the sensor. That test looks like it is ok though. They tend to flatline.

So... from here... looks like you have a leak. It is 20 years old.

You have the filler neck, top of tank, etc. to inspect. It tends to be a job for smoke.

Because while you said its holding vacuum valve closed, that only clears up to the valve, but it still can be anything after as it's saying the tank isn't building vacuum. Its when the valve is ON that it's sending vacuum down to the canister to suck up fumes.

So the tank, etc. is not eliminated as a cause but instead is what it's pointing too. You can with the vacuum gun back check from the tank towards the canister for line leaks/ test the canister, but then you've worked down to the tank where a leak can be a bit hard to find without some tools for it.

I think its likely a filler neck or something.
 

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Discussion Starter · #3 ·
Thanks, Reverend!

I noticed a gasoline smell earlier today when I filled up the tank to all the way full, it was more pronounced when I lifted off the rear seat bottom section. So I think you're right, it's probably something at the top of the tank. I think I'll change the fuel pump O-ring and the round plastic lock for the fuel pump too, for good measure. Who knows if they replaced those when the pump was replaced... if still showing P0455 then I'll have to do a smoke test.
 
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