Chevy Silverado P0452: FUEL Tank Pressure Low Diagnosis

A generic OBD II Code, P0452 may occur in your Chevy Silverado.  It means that your Silverado’s EVAP system has detected low fuel tank pressure.

The fuel vapors are sent from the tank to the intake to be burned.  The system generates P0452 if the pressure gets too low.

When P0452 is not the sole code you experience, don't consider it a breakdown danger. This can often be fixed with a new fuel cap.

A bad gas cap is often the cause of P0452

Signs

This is more often than not a sign of any serious illness. However, your Silverado should continue running normally.

Below are some common symptoms of this code.

• Check engine light (obviously)
• A smell of fuel indicates that there is a leak in the fuel tank or loose fuel cap.
• Hessing sounds (signals a vacuum leak)

Chevy Silverado - P0452

These are the most common reasons for P0452 in Chevy Silverado.

• Gas cap loose
• Wiring or bad fuel tank pressure sensor
• Canister full of charcoal
• Leakage of vacuum
• Failure of the EVAP purge solenoid

Chevy Silverado P0452 Diagnostic Procedure

Here’s a solid order of diagnosis when dealing with P0452 in your Silverado:

1. Look for other codes

Skip to next section if P0452 is your only trouble code.  If it is not, cross referencing the other code’s causes with the common causes of P0452 can really help you eliminate some possibilities.

2. The Gas Cap

P0452 indicates that your Silverado’s fuel tank pressure sensor has detected that the pressure in the fuel tank is too low.  This code is caused by a gas cap that isn't tight enough or not sealing well.

Inspect the fuel cap by removing it.  The rubber ring should fit snugly to the fuel intake.  A replacement will likely be required if the rubber ring is worn or dry-rotted.

OBDII codes can remain in your system even after you have fixed the problem.  If you believe that the fuel cap was loose, or you changed it, you’ll need to clear the code with a code scanner and see if it comes back or not.

You should also ensure that there are no obstructions to the fuel inlet.  If it has gunk built up or mud on it, you’ll need to use a wet rag or some WD-40 to clean it off.

If it does come back, we’ll need to move on to the next step.

3. Verify the fuel pressure readings

Although the problem is easily diagnosed by checking the gas cap, which more often than you think is the source of P0452's symptoms, it can be difficult.

A mechanic would use a professional OBDII scanner to check the fuel tank pressure readings from your Silverado’s fuel tank to see if there is vacuum in the tank.

If it doesn’t look right, the wiring to the fuel pressure sensor would need to be inspected.  

If that doesn’t help anything, the tank pressure sensor itself would need to be replaced.

If everything looks fine, they’d move on to checking the EVAP system.

4. EVAP System Questions

An EVAP failure can lead to P0452.  Here’s how a good mechanic would go about diagnosing it.  This video is worth watching if this is something you want to tackle yourself.

The Common Diagnostic Error With P0452

When diagnosing P0452, a common mistake is not to check the gas cap before doing so.  

Or, they’ll keep going on with the diagnostic process after addressing the fuel cap because they did not clear their trouble codes.

You can drive the Silverado while you tighten the gas cap. This will allow the code to clear before proceeding with diagnosis.

Chevy Silverado P0452 Conclusion

A bad gas cap is the most common reason for P0452.  It is possible to diagnose P0452 if the gas cap is in good condition.