Error Code P0443 is described as the Evaporative (EVAP) Emission System Purge Control Valve Circuit. This means one of the purge valve is malfunctioning or the purge valve circuit is short or open.
The ECM operates the ground circuit to control the valve, which opens the purge valve at specific time intervals, allowing gas to get into the engine. The ECM also monitors the ground circuit for faults. If the purge solenoid is not activated, the ECM should see high voltage on the ground. If it is activated, the ECM should show the ground voltage pulled to be low and close to zero. If the ECM can’t see the expected voltages, or detected open circuit, it will trigger the error code .
In this error code, the EVAP system allows the fumes to enter the engine to be burned, rather than expelling to the atmosphere as emission. The purge valve solenoid is supplied from the switched battery voltage, which means there’s an improper flow of purge in the EVAP system. This can be caused by a defective purge valve or a shorted purge valve circuit.
Unburned drops of raw fuel are harmful for health and the environment as it can cause breathing problems and contributes to smog.
The job of the EVAP emission system is to capture and keep any raw fuel and fuel vapor from the fuel storage system, which includes the fuel tank, fuel neck cap and filler neck. These captured fuel vapors are sent back to the combustion process by the EVAP system, under precise operating conditions, which is dictated by the speed, load and temperature of the engine.
This error code refers to an issue with the purge control circuit, not automatically the valve. The problem is usually in the unit that houses the valve and solenoid (in the assembly), or could be a defect of a individual solenoid with purge valve or vacuum lines. This means the problem could be a result of any of the following:
Step 1 – Get the code and jot down the freeze frame info for a baseline test and to verify your repair.
Step 2 – Check all accessible components and hoses in the EVAP system. Look for any signs of wear and tear.
Step 3 – Use a scan tool and check the Fuel Tank Pressure readings. If the Fuel Tank Pressure sensor is not working properly, the system will think there is no pressure or vacuum being made when EVAP monitor is done, even if there is actually pressure/vacuum being made. The PCM depends on the Fuel Tank Pressure Sensor’s leak test data when the EVAP monitor runs.
Step 4 – Check the fuel cap and make sure it fits nicely to the fuel tank filler neck. Also, make sure the cap seal is NOT cracked or dry. If the cap is unable to hold pressure/vacuum, then it will trigger the error code.
Step 5 – Check the Purge Valve, as well as the Vent Valve. Both should be able to hold vacuum for a specified amount of time (at least 30 to 60 seconds). If one of the valves is malfunctioning, the system will not respond and/or hold the right amount of vacuum.
Step 6 – If each of the components you check seems to be working properly, then your next test should be the ‘smoke test’ for the whole EVAP system. This test will search for any hidden leaks all throughout the under components of your 2008 Saturn Vue .
With your ground wire removed from the ECM, turn on the key and then ground the Purge valve control unit manually. There should be a ‘click’ sound from the solenoid. If there’s none, then there might be an opening in the wiring between the solenoid and the ECM. You need to find this opening and fix it
If there is a ‘click’ sound from the solenoid however, this means the control wire connected to the solenoid is in good shape, and the problem is in the ECM purge solenoid driver circuit of the ECM.
Parting Tips
For more about EVAP error codes, or for more comprehensive and thorough professional help, Contact Us.