DTC P0452 indicates EVAP Pressure Switch stuck closed. What does the code mean?

DTC P0452 Fuel Tank Pressure Sensor Circuit Low Voltage

The fuel tank pressure sensor is located on top of the fuel tank.

Circuit Description
The fuel tank pressure sensor measures the pressure (or vacuum) in the fuel tank. The powertrain control module (PCM) provides the sensor with a reference voltage, a signal circuit, and a ground. The sensor returns a signal voltage to the PCM relative to the pressure in the fuel tank. The PCM should see a signal voltage increase as the pressure in the tank decreases (more vacuum). As the pressure in the tank increases (less vacuum), the PCM should see a signal voltage decrease. The PCM uses the sensor signal to test the integrity of the EVAP system. If the PCM detects a signal voltage that is too low, DTC P0452 will set.


Your best bet , take your vehicle to a qualified repair shop.

Good explanation of the problem and suggestions at the link below.

https://www.obd-codes.com/p0452

the following links can assist you
P0452 EVAP Pressure Sensor Switch Low
P0452 EVAP Pressure Sensor Switch Low P0452 OBD II Trouble Code P0452 Evaporative Emission Control System Pressure Sensor Low Input How to troubleshoot an EVAP Pressure Sensor problem P0452 GM

P0452 Would indicate Evaporative emmision ( EVAP) pressure sensor low input , this could mean that there is a short in the sensor wiring leaning more towards a short to earth , the pressure sensor itself or as last resort the (ECM) as a rule the tubing leading from the gastank to the purge valve canister , the canister itself and the tube leading all the way to the intake manifold via the purge valve should not escape inspection. See if the gascap fits well and is properly in position .
Hope this helps a bit ,
Regards
Faldih Higgins

P0446 has nothing to do with the canistor !
DTC P0446 Evaporative Emission (EVAP) Vent System Performance
This DTC tests the evaporative emission (EVAP) system for a restricted or blocked EVAP vent path. The control module commands the EVAP canister purge solenoid valve Open and the EVAP canister vent solenoid valve Closed. This allows vacuum to be applied to the EVAP system. Once a calibrated vacuum level has been reached, the control module commands the EVAP canister purge solenoid valve Closed and the EVAP canister vent solenoid valve Open. The control module monitors the fuel tank pressure (FTP) sensor for a decrease in vacuum. If the vacuum does not decrease to near 0 inches H2O in a calibrated time, this DTC sets.
DTC P0452 Fuel Tank Pressure (FTP) Sensor Circuit Low Voltage


How to troubleshoot an EVAP Pressure Sensor problem P0452 GM

EVAP Vent Solenoid Code P0446 The solenoid is stuck open !

P0452 The definition is evap pressure system low. This mean it detected a no pressure but rather a leak, There is nothing wrong with the pressure sensor or wiring itself,Fist thing to check is the gas cap,make sure the seals is good shape, The hose connection are firm and clamped down,you basically have a evap leak

Do you mean "P0440"?

Diagnostic Test Code (DTC) P0440 has a generic description of "Evaporative Emissions System Large Leak".

The MOST COMMON cause of this code is refueling the vehicle with the engine running or not getting the fuel cap on correctly after refueling.

The Powertrain Control Module (PCM) checks for leaks in the Evaporative Emissions (EVAP) system using the data provided by the Fuel Tank Pressure (FTP) sensor. It will check the FTP sensor data, then close the EVAP Vent Valve and open the Canister Purge Valve to apply vacuum to the EVAP system. After a period of time, the PCM will again check the FTP data to see if the fuel tank pressure has dropped within a specified amount. If there is very little or no change in the FTP data, DTC P0440 sets.

Other possible causes for this code are:

> Defective FTP sensor (VERY RARE)
> EVAP Vent valve stuck open
> Canister Purge Valve stuck closed
> Large leaks or cracks in any of the EVAP system hoses and/or lines and/or components, including the fuel tank and the fuel filler neck and the EVAP canister

Please note that this code indicates a MECHANICAL failure of the system. This is NOT a circuit fault that would involve broken/shorted wires, blown fuses, etc..

DTC P0446 - Evaporative Emmission Control System Vent Control Circuit
Evap vent valve has only one purpose. It closes in order to seal the vent so the EVAP system can pressurize and ensure there are no leaks. Evap vent valve is usually supplied Batt. voltage with key on. The ECM's driver controls the ground, and when grounded, activates the valve (closing it). If the ECM detects a short to ground, and open,or a short to battery voltage on the control circuit, P0446 will set. Code also may refer to ECM detecting that EVAP system is unable to achieve or maintain vacuum during test. A code P0446 could mean one or more of the following has happened:

• Faulty vent valve
• Open, short or excessive resistance on Vent valve control circuit
• Blockage of vent valve
• Bad PCM

Possible Solutions

• Replace Vent valve
• Repair open, short, or resistance problem in control circuit
• Repair open, or short, or resistance problem in power circuit
• Replace PCM

DTC P0452 - Evaporative emission control system, pressure sensor low imput
DTC P0453 - Evaporative emission control system, pressure sensor high imput

The PCM monitors the EVAP control system FTP sensor input signal to the PCM. The test fails when the signal average jumps above a minimum allowable calibrated parameter. If both codes are present, it sounds like your fuel tank pressure sensor has failed.

The sensor is on top of the tank and you will have to remove the tank. But your symptoms are pointing to more than just the sensor. You may have wiring problems.


Hope this helps (remember to rate and leave a comment about this free answer).

Continuous Memory Diagnostic Trouble Code (DTC) P0446 or P1450 indicates that Self-Test has detected the Evaporative Emission Control System has excessive fuel tank vacuum. Also, a DTC P0446 indicates a vent control malfunction.

Possible causes:

EVAP canister purge outlet tube (EVAP canister purge valve to EVAP canister) blockages or kinks.

EVAP canister tube (fuel tank to EVAP canister) blockages or kinks.

Fuel vapor elbow on EVAP canister contaminated.

Restricted EVAP canister.

Canister vent (CV) solenoid stuck closed (partially or fully).

Plugged or contaminated CV solenoid filter.

EVAP canister purge valve stuck open.

Fuel filler cap stuck closed (no vacuum relief).

VREF circuit open in fuel tank pressure (FTP) sensor.

Damaged FTP sensor. (fuel tank pressure)

Check for kinks or bends in the fuel vapor hoses/tubes (EVAP canister purge outlet tube and EVAP canister tube).

Visually inspect EVAP canister inlet port, CV solenoid filter and canister vent hose assembly for contamination or debris.

Check CV solenoid filter for blockage or contamination.

The common things I've seen are are mud in the canister and the canister vent solenoid being shot or the wiring to the canister vent solenoid being torn off. The resistance of the solenoid should be 48-65 ohms..
Pick up a Chiltons book and will give you a diagram of where exactly you find the canister. They are like $15 at any auto store. Good luck

Check for a loose hose on the purge valve