P0443 - EVAPORATIVE EMISSION CONTROL SYSTEM PURGE CONTROL VALVE

The EVAP system (The evaporative emission control system) is responsible for controlling the vapors from the fuel tank so that they enter the engine and are burned instead of being expelled into the atmosphere. It consists of a solenoid that goes into the purge valve and this provides changes in battery voltage.

The ECM (Engine Control Module) inspects the valve by activating the ground circuit, and thus, the purge valve opens at specific times, allowing these gases to enter the engine. Similarly, the ECM controls the ground circuit, which allows troubleshooting.

When the purge solenoid has not been activated, the ECM (Engine Control module) should perceive a high voltage in the ground circuit, when the solenoid is activated or working properly, the ECM should see the ground voltage at a low level, this is very close to 0.

If the Engine Control Module (ECM) does not observe the expected voltages or concludes that there is a short in the circuit, the diagnostic code P0443 is set.

• The Check Engine light is on.
• Engine operation may be erratic.

A code P0443 can be caused by one or more of the following problems:

• There can be a short circuit in the purge solenoid.
• Perhaps, a cable may be threading with some component and so there is a short circuit, likewise, the connectors may be worn out or shorted due to the presence of water.
• The controller circuit inside the PCM (Powertrain Control Module) may be defective.

To solve the DTC code P0443, you can check the following components:

• Using a scan tool, you command the purge solenoid to activate. Then, listen to the sound to make a click to verify it is activated.
• In case the respective sound is not heard, you should unplug the connector and make sure that it is not damaged or waterproof. Check the battery voltage on the power cable with the ignition key, in case you have the battery voltage, ground the control side manually using a cable as a jumper and see if it clicks on the valves. If it does, it is an indication that the solenoid is working properly and the problem is in the control circuit. If it does not click, you can change the purge solenoid.
• Check the wiring between the ECM (Engine Control Module) and the solenoid for a short circuit, repair if necessary.