1998 Chevy Blazer Fuel pump code fuel sensor low pressure

  • 6 CYL
  • 4WD
  • 11,300 MILES
I have a 1998 Chevy Blazer 2DR 4 wheel dr. When we bought the vehicle it had a gas tank leak. We bought a new gas tank and installed it to find that the pump wouldn't work. We dropped the tank again and installed a new fuel pump and got the truck running again. A couple days later the check engine light came on. We had it tested and the code for the fuel pump sensor located on top of the fuel pump came back stating low pressure. We also noticed in the meantime that the gas cap was broken off. We think someone tried to steal gas because neither of us broke this. Now when putting gas in the truck we have to unscrew the bottom part of the gas cap and we hear pressure releasing like when you open a bottle of pepsi. After I put gas in the truck the check engine light went out. Any suggestions before I pull this tank down again. And if the sensor is bad could I use the sensor from the old pump I took out and install it on the new pump?
Do you
have the same problem?
Tuesday, November 11th, 2008 AT 3:40 PM

1 Reply

Hello -

If this doesn't work then please make sure you provide the exact engine size in liter and he 8th digit of your VIN.

Many vehicles will throw a code if the gas cap is not on properly. The tank must have certain pressure to operate effectively. It may be, since your gas cap was broke it was unable to hold the correct pressure and the pressure sensor detect this and threw a code.

My suggestion is replace the cap with a new one and have all the codes cleared. Then drive it and see how it does. Then check the codes again. If you need to get back with us please make sure you provide what the code number is and what they said it means.

You can go Auto Zone or O'Reilly's and for free they can pull the codes to the car and clear them. Most important. Once they check your codes, if they find something and you don't get it fixed and need to get back with us, please make sure you tell us exactly what the code was, number and all. Example, if the code was E0568 O2 Sensor bad. Then make sure you give us all of that. While there for free also they can bring their tester out and check your battery, alternator and starter.

I have attached what the cap does to assist you as well. It is normal for pressure to release, as you said like opening a can of Pepsi.

I just hate for you to drop the tank again, (not much fun) if you don't have to.

Again, if this doesn't t work, then please get back with us.

The fuel tank filler neck is equipped with a screw type cap. The threaded part of the cap requires several turns counter-clockwise to remove. The long threaded area is designed to allow any remaining fuel tank pressure to escape during the cap removal operation. A built-in ratchet type torque limiting device prevents over-tightening. To install, turn the cap clockwise until a clicking noise is heard. This signals that the correct torque has been reached and the cap is fully seated. A fuel filler cap that is not fully seated, may cause a malfunction in the emission system.

NOTICE: If a fuel filler cap requires replacement, only a cap with the same features should be used. Failure to use the correct cap can result in a serious malfunction of the system.
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Tuesday, November 11th, 2008 AT 7:19 PM

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