P0449 Evaporative Emission Control System Vent Valve/Solenoid Circuit Malfunction

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P0449 Evaporative Emission Control System Vent Valve/Solenoid Circuit Malfunction

OBD-II Trouble Code Technical Description

Evaporative Emission Control System Vent Valve/Solenoid Circuit Malfunction

What does that mean?

This code is a generic powertrain code. It is considered generic because it applies to all makes and models of vehicles (1996-newer), although specific repair steps may vary depending on the model.

The Powertrain Control Module (PCM) / Engine Management Computer (EMC) / Engine Control Module (ECM) has detected a fault with the circuit that controls the vent for evaporative emission systems vapor.

As fuel sits in the tank it lets out fuel vapor, while driving this vent opens and allows the vapors to be circulated into the engine intake manifold, a charcoal canister or into the atmosphere, depending on the vehicle. This vent valve is apart of the simple, yet complicated evaporative emissions system.

Symptoms

Symptoms of a P0449 DTC will include Malfunction Indicator Lamp (MIL) illumination, you will likely not notice any other symptoms.

Causes

Potential causes may include:

  • Faulty vent valve
  • Wire/circuit issue
  • PCM/EMC/ECM fault
  • Possible Solutions

    Some steps to take to diagnose and repair this trouble code include the following:

    Check your fuses, there may be a fuse that powers the vent solenoid.

    Check for a rubbed-through or chafed wiring harness. Check both wires to see if they are shorted to each other, to ground or power.

    Visually inspect the vent valve for cracks or damage.

    Trace the wires to and from the PCM/EMC/ECM and check for continuity continuity using a digital volt ohm meter (DVOM).

    If you have access to an advanced level scan tool, actuate the valve while reading power and ground at the connector or by simply using a bulb wired to both terminals, it will light up if power and ground are OK.

    Using a DVOM, check the resistance of the vent, in most cases the resistance reading should be low, refer to the manufacturer’s specification or compare it to a new one. Too high or low a value indicates a faulty coil inside the valve, thusly meaning replacement is necessary. This code seems to be prevalent on Dodge, Chrsyler, and Jeep products. In those cases the vent valve was bad. With GM products (specifically pickups), GM has released a new updated valve assembly.

    Finally, remove the valve, you may be able to access the pintle inside and it simply could just be sticking from fuel residue. Clean it and retest.

    Other EVAP DTCs: P0440 – P0441 – P0442 – P0443 – P0444 – P0445 – P0446 – P0447 – P0448 – P0452 – P0453 – P0455 – P0456

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    "Delete Error Code Permanently, Disable DTC Error Code Function for p0449 in the ECU"

    In extreme cases, we even have the option to permanently remove the specific DTC p0449 and disable the function of the specific error code in the ECU. All other fault code functions will then continue to work to protect the engine. This is different from clearing an error code with a diagnostic device. We have the option to permanently remove the function of the specific error code, so that it never comes back. Also emergency running that occurs on the specific error code can be solved in most cases.

    Of course we prefer to first try to solve the cause of the error code, but sometimes the only solution is to permanently disable the DTC function of p0449.

    Make an appointment for permanent removal of p0449