Question about p0453 on 01 LS V8

... What about the jet pump/sending unit on the drivers side could cause this ? ...

It's not impossible, since the PCM has to know about how much is in the tank to do the pressure tests. Use a scan tool to determine which of the senders is sticking (electric fuel pump side or jet pump side).
 
I think that most (like the LS) depressurize (pull a partial vacuum) instead of pressurize.
 
It's not impossible, since the PCM has to know about how much is in the tank to do the pressure tests. Use a scan tool to determine which of the senders is sticking (electric fuel pump side or jet pump side).
I will test the passengers side pump out but I recently replaced that one so I highly doubt that would be the problem but I guess you never can say never with these car parts. But I did go ahead and order the Drivers side unit just now brand new OEM for $150 shipped because I do feel like it's starting to go bad with how slow it is to read the gas in the tank and I know you don't want that part to fail cause I have had it happen before on a newer LS and it left me stuck on the road with more than a 1/4 of tank of gas in it. It was hard to pass that deal up cause I know how much they usually go for. I realize it may not fix my problem but as I plan to keep this car for many, many years! It's a good thing to have in sound shape as old as the car is. It's always a good thing to have a accurate idea of how much gas is left in the tank!
 
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I went out and looked on the drivers side and I can now get access to the harness it's still tight but he was able to position it so that it can be tested. So I am looking around my house I could have swore I had a meter. Then what do I need to test myself exactly since I should have access to the harness. I am not good at all with electrical stuff so please be patient with me! Also ran a few tests with Forscan
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What is the proper way to test that FTP sensor connector for the correct voltage? I have someone coming over to my house to look at the car to see if they can find the issue. I just wanted to have good info to give them on the proper testing procedure for that.
 
The Fuel Tank Pressure Sensor input circuit is checked for out of range values (P0452 short, P0453 open), noisy readings (P0454 noisy) and an offset (P0451 offset).
Note that an open power input circuit or stuck check valve generates a P1450.

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The Yellow/violet wire to the sensor is the reference supply. It is the same signal as the Yellow/violet wire to the AC pressure sensor under the hood. It goes to pin 55 of the PCM. This signal is okay at the AC pressure sensor, or the AC wouldn't be working. It should probably be 5.0 volts, but is not specified.

The Brown/white wire is the ground to the sensor. It should be at zero volts. If not, it is the problem.

The White/violet wire is the signal from the sensor. This is where the voltage above is measured. It should be close to 2.625 volts just sitting there with the fuel cap off. It goes to pin 42 of the PCM.
 
Just thought I would post a picture so people would have an idea where the FTP sensor and connector actually are in the 00-02 LS. I also assume it's similar in the other models.
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Where you see the Yellow Heat Shrink that is the connector to the FTP sensor. I am not sure if it's like this exactly on the other LS's but mine is easier to see now since I replaced the harness and the FTP sensor.
after-1.jpg
 
I went out and looked on the drivers side and I can now get access to the harness it's still tight but he was able to position it so that it can be tested. So I am looking around my house I could have swore I had a meter. Then what do I need to test myself exactly since I should have access to the harness. I am not good at all with electrical stuff so please be patient with me! Also ran a few tests with Forscan
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My fuel tank Pressure sensor is reading a steady 1.0 when car is at idle in Park I see yours is 4.2 ...was car in Park and at idle in your Forscan Data Photo you posted?
 
My fuel tank Pressure sensor is reading a steady 1.0 when car is at idle in Park I see yours is 4.2 ...was car in Park and at idle in your Forscan Data Photo you posted?
Yeah it was parked and was at normal idle. And it does not move around with taking the gas cap off nor does it change if accelerating in park. I am hopefully going to have more of an idea what the problem is after tomorrow.
 
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I went to the mechanic today and all the power is correct but he found that the FTP sensor lines are not clamped, so he thinks there is a chance that is the cause. He also is suspect of my intake leaking and is gonna smoke test my car. I know I don't have a code for a lean condition but I guess there is always still a chance. He thinks at this point that it's possible to have a valve sticking in the evap system or the rear canister is bad. I have to address the issue with the fuel lines though cause I can smell the gas pretty strong back there. I am hoping that is the only problem for the P-0453! Also are these intakes known for cracking on the Gen 1? I was trying to find a new OEM replacement but the price for what I could find is beyond what I am willing to put into this car. I know I won't have much clue till he does this smoke test but I am just trying to prepare myself. Do the intakes fail much or is the usually the intake gaskets that leak?
 

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