GMC Sonoma P0452 - FUEL Tank Pressure Low Diagnosis

The OBD II generic code P0452 can be found in your GMC Sonoma.  It means that your Sonoma’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.  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. It can usually be fixed with a new fuel cap.

Bad gas caps are more frequently responsible for P0452

Signs

P0452 will not usually be associated with any visible symptoms. The Sonoma 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.
• A hissing sound is an indication of a vacuum leak

GMC Sonoma Causes of P0452

These are the most common reasons for P0452 in GMC Sonoma.

• Capacity for gas is not required
• Low fuel tank pressure sensor, or wiring
• Charcoal canisters that are clogged
• Vacuum leak
• Failure to purge the solenoid of EVAP

GMC Sonoma P0452 Diagnostic Procedure

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

1. You can also check for additional 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 Sonoma’s fuel tank pressure sensor has detected that the pressure in the fuel tank is too low.  The code can be caused by gas caps that are not tightly sealed or which do not seal well.

Take off the fuel cap.  The rubber ring should fit snugly to the fuel intake.  It is possible to replace P0452 if it has become dryrotted or is damaged.

OBDII code codes remain in the system until the issue is resolved.  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. Take fuel pressure measurements

Diagnostics of P0452 can be difficult, besides checking your gas cap.

A mechanic would use a professional OBDII scanner to check the fuel tank pressure readings from your Sonoma’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 issues

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.

The Common Diagnostic Error With P0452

When diagnosing P0452, a common error 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 then drive the Sonoma for several minutes to verify that the code is clear before you move on with your diagnosis.

GMC Sonoma 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.