2001 Saturn SL2 EVAP code P0452

That code has nothing to do with a leak it say's that you have a reading of of less then .1 volt from the pressure sensor back to the pcm for greater then 3 second's.So i would be checking the connector and wiring to your pressure sensor.I also emailed you the info on that code.

Checked all connections. everything is good (except the purple wire to the starter but that is irrelevant to the evap system). I have suction from the throttle body to the EVAP solenoid but no pressure or suction from the tank. I put pressure to the tank with an external air hose and the only place I could hear or see it come out (smoke test) was by the gas cap with the cap off, no visible pressure release with the cap on. there has to be a leak by the canister even though I cant find it.

I am now also getting error P0405 and P0404 and a surging while I am driving. so in addition to the Evap system I probably have a bad O2 sensor or EGR problem. OH JOY!

That code P0452 is not caused by a leak it's caused by circuit issue,bad pressure sensor,or a bad pcm.Most likely it's a circuit issue.There are different code's you get for leak's so your barking up the wrong tree by looking for leak's.The P0404 is for most likely a sticking egr i would remove the egr valve and slowly push down the pintle till it bottom's out and then slowly take the screwdriver away from the pintle.See if the pintle closes all the way and doesn't stick.But from the surging and the code's it sound's like it's sticking.I also emailed you the info on the p0404.

The 452 error started last winter when a Chunk of asphalt kicked up and streached the fuel line and tore the evap line. I replaced the fuel line and bridged the evap line. I keep saying I am looking for a leak because of this. I have already replaced the EVAP selonoid because when the hoses pulled it broke the unit off of the bracket. I also double checked (and triple checked) the wires in the area of the selonoid. I droped the gas tank and could not see any signs of damage from the pull. Where is the other sensor or wiring harness I should replace/check.

Today I pulled the EGR valve and attempted to clean it. It did not seem to stick but it was carboned up a lot. The car is still surging so I may grab one from a junk yard to see if ireplacing it makes a differance.

I am about ready to take it to a shop and let someone else give it a shot. with 170k on the car and all the other minor problems added in, I just cant justify droping a lot of money to fix it. If it were not for NJ inspection I would just drive it utnil it dies.

Thanks Aain for the info.

I posted the the trouble tree for your code P0452 and i emailed it to you also can you please show me where in the trouble tree they have you look for a leak?Let me know how you think a leak will cause the voltage reading to be so low on the fuel tank pressure sensor.I'm not trying to argue with you just trying to get you to understand what the code really mean's.Because there is a code for a large leak and a small leak if you had a leak you would have set one of those code's.

I am not arguing either. I agree that it is electrical. There is a low voltage issue at a sensor related to the evap system. That is why I repalced the EVAP soleniod on the motor. I am using the work leak but I understand that it may be that a sensor, related to one of the lines that got pulled, took a wack and is not functioning. I am out of Ideas of what to look for and where. There is suposed to be a sensor on top of the gas tank and I did not see it when I pulled the tank the last time. When I am down to empty again I will drop the dank one more time. If I cant find a problem again I will just replace the tank, lines and sensors with one out of the junk yard.

It's not some sensor your looking for a problem with it's the the fuel pressure sensor and wire's your looking for a problem with.It's on top of the gas tank.You need to read the info i sent you it tells you that's what your looking for.I thought you were reading the stuff i sent you no wonder your looking for a leak.I posted a diagram that show's you the sensor location you can see it next to the fuel pump.I also posted the pressure sensor connector it show's which terminal letter is which.When you drop the tank down turn the key to the run position and your terminal c to the pressure sensor should have 5 volt's to it.When you get the tank down let me know and what you find also check terminal tightness.You will have more to check when the tank is down.

I have been reading what you sent me. I hate to admit that when it comes to electrical I am at a bit of a disadvantage, I have a multimeter but only have the basic knowledge of how to use it. I am a back yard mechanic. I can rebuild a motor or bread system in record time but when you put a circut diagram in front of me it takes me a while to figure it out and then only if im lucky.

Picture a realy smart monkey then put a set of glasses on him and add a test light, that is me when it comes to computer controled electronics..

Well your going to need a multimeter to test that circuit.I will help you the best i can but you may have to take it somewhere to have it checked out if your just a smart monkey with glasses and a test light lol.Let me know when you get that gas tank down.

see next post. corected information with new more detailed.

I checked and I have 4.98 v at both color coded terminals. I am assuming that the white wire (terminal A) is ground. from what you have told me this should not be the case. these wires must be contacting somewhere? One should be a signal from the computer at 5v to the sensor and the other should be the return signal from the sensor to the computer?

Turn the key off and see if those two wire's that have the 4.98 volt's have continuity between them use a multimeter on low ohm scale like 200 ohm scale.

Had continuity between terminal A & B with key off. also had continuity between A (orange and black)and body (makes sense, think that is the ground) and B (green) and body. Could not find a break in the harness but after moving the harness and testing at the junction block by the kick pannel I now do not have continuity and I do still have 4.98 on terminal C (grey). when contacting A & B or B & body I get a fluctuating #, not O.L for continuity. being I can not find a break and the orange & black does not go all the way forward I would think I could just abandon the existing wire, reground terminal A to the body and run a new green wire from the junction block. I will wait for a response before I burn out the computer or something.

If we solve this problem and I dont have to replace the car I will deffinatly make a "donation". I know you have helped a lot so far and it may not be fair to say payment is depending on outcome but I dont have any extra money if I have to replace this thing. Regardless you have my thanks.

All three of them shouldn't be connected to each other at all.Terminal A is grounded thru the computer and you shouldn't ground that to the body.Terminal B is your return wire for the pressure sensor circuit and terminal c is your 5 volt feed.It sound's like your terminal A and B where connected together some where and when you moved the wire's around they got discounted.That would explain the code setting.I would make sure those wire's aren't connected anymore and see if you can find where they were connected and go from there.

I understand that these are seperate and should not cross at any point. I will follow the harness as far as I can. There is no orange/black wire at the junction block by the kick plate. do you know where this wire splits off from the main harness. If I can not find a break or exposed spot on the wire i will just run a new green wire from the junction block to the plug then cut the original wire at both ends.

If the orange/black wire is contacting somewhere it should not matter once the other wire is disconnected.

should I replace the sensor, since the wire was shorted, while i have the tank out

The orange and black wire goes from the sensor to the gray 68 way connector on the back side of the inside fuse box and come's out of the black 68 way to the computer.That's what i see in the wire diagram i have the wire color stay's the same color the way thru the circuit..I doubt the sensor was damaged from the wire's touching.That's up to you if you want to change it for good measure.If you do decide to change the sensor let me know and i will help you find a good price on one.

I traced all the wires and could not find a break anywhere. I disconnected the wires from the computer and jumpered the gound to the other two wires one after another (after ensuring I had a good ground with the computer disconnected) to verify that I was working with the correct wires by the fuse block. removed jumper, reconnected plugs to computer and ran a new green wire. checked voltage at Terminal C. 4.98, B nothing, A ground. Reinstalled the gas tank and started the car. Ran for about 30 seconds and the check engine light came on. I will get the reader this weekend and verify it is the same code but I am sure it is.

If you have another idea I will give it a try but I think the car is done.

Thanks for trying

What you really need is to find is a scan tool that will read live engine data that read's the voltage of your fuel tank pressure sensor so we can see what is going on there.If the wire's are squared away the only thing left is the sensor or the computer.Let me know what code you have now.

still code P0452. EGR Codes did not come back. I will have someone with better equipment plug it in and see what they get. A and B have continuity again. When i get it to break continuity I still get a fluctuating # not 0.L ... Think this indicates that there is something jumped in the computer but I will still get someone to plug it in and verify.

Thanks

Unplug the connector's to the computer and see if there still connected that will eliminate the computer.

Return voltage to computer (green wire) was 1.5 with about 2 gallons in the tank and was 1.48 after filling the tank then driving about 40 miles. ( the tank is still basically full.

voltage to grey wire maintained 4.98 regardless of time it was checked. orange/black is still a good ground signal.

The return voltage is what the computer read's with no pressure in the tank gas cap off it should read 1.2-1.5 volt's that is a normal reading.So far so good sounds like with those reading's.

That sounds like the presure sensor is doing what it is suposed to. That to me indicates even more towards the computer. A computer is around $600 then I have to get it programed for the vin so I am sure that will be expensive. I will still plan on having somone hook it up to better equipment but I was hopping you would say the signals should be .1 at empty and 5 at full. I never get that lucky. thanks for getting back to me on a saturday

The fuel level has no bearing on the pressure sensor reading.What effect's the reading is the vacuum level in the gas tank.If your going to throw a computer at it please don't spend all that money on a new one get a used one there a lot cheaper and already programed.You could probably find one for like 50 i would go for a used one if it was my car.The computer's hardly ever fail on those car's.

I'm not going to throw a computer at it. I will have someone that can get live data to check it out before I do any more.

If it does need a computer I can get a junk yard one but still have to have someone flash it with the correct VIN and mileage. NJ inspection is now just a matter of type the vin into a computer and plug the OBD 2 port in. all sensors read good and the data matches, then you pass. Anything disagrees or fails you don't.

I just don't see how the computer could have coincidently gone bad at the same time a chunk of asphalt decided to jump up and dent a floor-pan, stretch a fuel line and snap a EVAP line. I don't doubt it, I just don't see how they are connected.

So when you hit this chunk of asphalt did it start setting this P0452 from that point on?It sound's like you more then likely just have a couple of wire's shorting together from what you have tested.Like i said the computer's don't fail often.I don't remember the mileage being stored in that model saturn the vin but not the mileage.The mileage is stored in the bcm.