Replaced gas cap....
'01 SS 3.8 L
And now I have a P0446 code? Had a gas cap that was not sealing it would "click" when turned but then I could simply pull it right off. Been reading around about this code and is it caused by something in the engine bay? Or something located back by the gas tank? I can't really get a grasp on what it is that is throwing this code. On a side note....when I replaced the gas cap that got rid of my P0420 code. :congrats: |
This should help..:thumbsup:
P0446 - OBD II Trouble Code Auto Systems and Repair Evaporative System Vent Control Circuit Malfunction Our emissions expert has put together the following information about the P0446 fault code. We have also included diagnostic procedures you can take to your repair shop if the mechanic is having difficulty analyzing the code. OBD II Fault Code
The evaporative control (EVAP) system captures any raw fuel evaporating from the fuel storage system (e.g. the fuel tank, filler neck, and fuel cap). Under precise operating conditions—dictated by engine temperature, speed, and load—the EVAP system stores and purges these captured fuel vapors back into the combustion process. The carbon canister, which stores the raw fuel vapors, utilizes a vent valve that allows fresh air to enter the EVAP system. This displaces the fuel vapor as it's purged into the combustion process. Code P0446 indicates that there is an improper voltage drop in the EVAP Vent Valve circuit, which can be caused by either too little or too much electrical resistance. This improper electrical condition will cause the vent valve to malfunction. Symptoms
The EVAP system is designed not only to capture, store, and purge any raw fuel vapors that leak from areas in the Fuel Storage system, but also to run a series of self-tests that confirm or deny the operational and vapor holding ability of the system. This is an important task because at least 20 percent of vehicle-produced air pollution originates from malfunctioning Vehicle Fuel Storage systems. There are many ways to "leak test" the EVAP system, but most perform the leak test when the vehicle is sitting (like over night) or during the initial start-up after the vehicle has been sitting over night. The EVAP system's operational performance is also tracked by the Powertrain Computer by reading the change in the oxygen sensor voltages and short term fuel trim whenever the stored vapors are released or "purged" back into the combustion process. These values should indicate that fuel is being added to the system and that the overall mixture is getting richer. The purging process occurs when the vehicle is under acceleration, which is when most vehicles require additional fuel. P0446 Diagnostic Theory for Shops and Technicians Some PCMs will trigger this code if the the proper level of vacuum was not reached during a leak test and the EVAP system contains a bypass valve that isolates the fuel tank from the carbon canister-vent valve assembly. This vacuum is measured and monitored by the Fuel Tank Pressure Sensor. The vacuum can be too high and for too long (stuck closed vent valve) or it can be too little or non-existent ( stuck open vent valve, a leak in the system or a defective fuel tank pressure sensor). Here is how the evaporative leak test is performed by the Powertrain Computer:
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