Definition of the P0446 code
P0446 is an OBD2 diagnostic trouble code that indicates a fuel vapor emission control system failure. Other EVAP system codes may be seen with P0446.
What P0446 code means
The P0446 code is activated by the ECU when there is a malfunction in the vent control valve of the EVAP control system. The ECU controls this valve as part of the EVAP control system, and an engine control light appears on the instrument panel when a malfunction is detected.
What causes the P0446 code?
- Defective, missing, or damaged fuel cap.
- Defective EVAP system line
- Fuel tank leakage
- Defective or defective carbon cartridge
What are the symptoms of code P0446?
- Check if the engine light is present.
- There may be a smell of fuel, and fuel consumption may decrease slightly.
How can a mechanic diagnose the P0446 code?
- Use the scan tool to see if there are any codes and note the freeze frame data.
- Erase all codes from the vehicle computer.
- Perform a road test of the vehicle to confirm the claim.
- Perform a visual inspection of all components of the EVAP system for damage to the fuel cap, fuel tank, EVAP hoses, and charcoal canister.
- Inspect the fuel cap for damage and make sure it is tight using a fuel cap tester.
- Uses a scan tool to monitor tank pressure data to make sure the reading is correct.
- Performs a self-test of the EVAP system using a scan tool to verify the operation of all valves and solenoids
- Perform the EVAP system smoke test if none of the above tests give conclusive answers.
Most common errors in the diagnosis of P0446 code
Errors can often occur with the P0446 code when care is not taken to perform all the steps without skipping any of them. The P0446 code can be caused by many different components, so care should be taken to properly check all of them to avoid misdiagnosis.
How serious is the P0446 code?
The driver usually does not notice any symptoms of P0446 other than the check engine light coming on. The P0446 code does not prevent the car from driving properly, but like any check engine light, it should be repaired as soon as possible to ensure normal operation of the vehicle.
What repairs can clear the P0446 code?
Repair or replace the fuel tank, if necessary.
Replace the fuel cap
Replacing the charcoal container
Replace EVAP wires
Additional notes on code P0446
Without the proper tools, EVAP system codes such as P0446 can be very difficult to locate. If a leak is suspected, technicians use an EVAP system smoke tester. The smoke test will show any leaks that were not previously visible, since leaks are usually much smaller than the human eye can see.
The advanced scan tool is another tool used in diagnosing code P0446. These scan tools do much more than just scan codes and clean them up. They allow you to view the ECU data live and see the changes over time.
Also, in the case of EVAP system codes, a high-quality scan tool will allow you to perform an EVAP self-test. These tests are performed to command the vent and purge solenoid on and off, as well as to test the system and determine where the fault or leak in the system is coming from.
