Error P0446 – how to fix?

Code definition P0446

P0446 is an OBD2 diagnostic trouble code that indicates a fault in the evaporative emission control system. Other EVAP system codes may be seen from P0446.

What does the code P0446 mean

Code P0446 is activated by the ECU when a fault occurs in the EVAP control system purge regulating valve. The ECU controls this valve as part of the EVAP control system and a check engine indicator light appears on the dashboard when a fault is detected.

What causes the code P0446?

• Faulty, missing or damaged fuel cap.
• Damaged EVAP cable
• Leak in the fuel tank
• Damaged or defective carbon cartridge

What are the symptoms of the P0446 code?

• Check Engine light is present.
• You may smell fuel and fuel consumption may be slightly reduced.

How can a mechanic diagnose the P0446 code?

• Use the scanning tool to check if the codes are present and note the data from the frozen frame.
• Erase all codes from the vehicle computer.
• Carry out a road test of the vehicle to confirm the claim.
• Visually inspects all EVAP components for damage to the fuel cap, fuel tank, EVAP hoses, and charcoal canister.
• Checks the fuel cap for damage and makes sure it is tight using a fuel cap tester.
• Uses a scan tool to monitor the tank pressure data to make sure the reading is correct.
• Performs an EVAP system self-test with a scan tool to verify the operation of all valves and solenoids
• Perform the EVAP System Smoke Test if none of the above tests are conclusive.

The most common errors when diagnosing the P0446 code

Errors can often occur with P0446 code when attention is not paid to executing all steps without skipping any of them. The P0446 code can be caused by many different items, so be sure to check all of them correctly to avoid misdiagnosis.

How serious is the P0446 code?

The driver usually does not notice any P0446 symptoms other than the lighting of the check engine light. The P0446 code does not prevent the car from driving properly, but like any check engine indicator light, it should be repaired as soon as possible to ensure normal vehicle operation.

What repairs can remove the P0446 code?

Repair or replace the fuel tank as needed.

Replace the fuel cap

Replace the charcoal container

Replace EVAP wires

Additional notes regarding 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 smoke tester. A smoke test will reveal any leaks that have not been seen before, as the leaks are typically much smaller than the human eye can see.

The Advanced Scan Tool is another tool used in the diagnosis of the P0446 code. These scanning tools do much more than just check codes and erase them. They allow you to view the ECU data live and see changes over time.

Additionally, in the case of EVAP system codes, a high-end scanning tool will allow you to perform the EVAP self-test. These tests are performed to command the purge and purge solenoids on and off, and to test the system and identify the location in the system where the failure or leak is originating.