Buick Rendezvous: Low FUEL Tank Pressure Diagnosis

A generic OBD II Code, P0452 may be present in Buick Rendezvous.  It means that your Rendezvous’s EVAP system has detected low fuel tank pressure.

Evaporative emissions control (EVAP), which sends fuel gas from the fuel tank, to the intake manifold for burning off, is called the evaporative emission control system.  If the pressure is too low in the system, then P0452 will be generated.

When P0452 is not the sole code you experience, don't consider it a breakdown danger. A new fuel cap will most likely fix this problem.

Bad gas caps are more frequently responsible for P0452

The symptoms

More than likely, the symptoms of P0452 will not be apparent. Rendezvous will run normally.

Below are some common symptoms of this code.

• Check engine light (obviously)
• You can smell fuel, which indicates a loose fuel cap (or EVAP leak).
• Hessing sounds (signals a vacuum leak)

Buick Rendezvous - P0452

These are the most common reasons for P0452 in Buick Rendezvous.

• Capacity for gas is not required
• Low fuel tank pressure sensor, or wiring
• Canisters clogged with charcoal
• Vacuum leak
• Failure to purge the solenoid of EVAP

Buick Rendezvous Diagnostic Procedure P0452

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

1. Look for other codes

You can skip to the next section if you only get P0452.  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. Seek out the gas cap

P0452 indicates that your Rendezvous’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.  You should pay attention to how the rubber ring fits into the fuel inlet.  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.

Make sure there is nothing blocking 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

P0452 diagnosis can be difficult, if not for the simple task of checking your gas cap.

A mechanic would use a professional OBDII scanner to check the fuel tank pressure readings from your Rendezvous’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.  If you're going to attempt this task yourself, it is well worth the effort.

An Often Mistaken Diagnostic With P0452

People make the common error of diagnosing P0452 by doing anything without checking the gas cap.  

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 then drive the Rendezvous for several minutes to verify that the code has cleared before you proceed with your diagnosis.

Buick Rendezvous 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.