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P0444 – What Does It Mean and How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.

Definition

P0444 is an OBD-II Code that refers to Evaporative Emission System Purge Control Valve Circuit Open

Meaning

A P0444 code is a general diagnostic trouble code that occurs when the ECM/PCM detects an open circuit in the evaporative emission system purge control valve circuit. The engine absorbs extra gasoline vapors from the fuel tank, which would otherwise be vented into the environment, thanks to evaporative emission control systems known as EVAP.

The PCM monitors the voltage at the purge control valve and detects any changes in it and if notices a problem with the purge valve’s circuit, it records an error code of P0444.

Causes

Common causes for this code include:

  • Disconnected or loose wiring harness
  • Open circuit engine wiring harness
  • Open circuit purge control solenoid
  • Defective PCM (rare)

Symptoms

The symptoms of a P0444 code are:

  • Illuminated Check Engine Light
  • Excess fuel vapors can give off an odor
  • The fuel efficiency might begin to decline
  • Engine may idle, stall or hesitate

Diagnosis

To diagnose a P0444 DTC code, a technician would:

  1. Scan for codes in the ECM and look at the freeze frame data for failure.
  2. Visually inspect the evaporative emission control system for leaks
  3. Test the circuit continuity of the purge valve connector and solenoid with a multimeter
  4. Check the operation of the purge control valve by commanding it on and off with a scan tool.
  5. Retrieve any history codes and compare them to the current codes.
  6. Clear all codes and test-drive the vehicle.

Common mistakes

The following are some of the most common mistakes that a technician may make when diagnosing a P0444 code:

  • Not thoroughly inspecting all the wiring and connectors for damage.
  • Not checking the operation of the purge valve with a scan tool.
  • Failing to clear all codes and test-drive the vehicle after repairs are made.

How serious is this?

A P0444 code is a moderate severity issue because it can cause fuel efficiency to decline and emissions to increase. The engine may also run poorly or stall as a result.

What repairs can fix the code?

The following are solutions that may fix this problem:

  • Broken or faulty wirings must be repaired or replaced
  • The vacuum hoses or lines must be checked for leaks and replaced if necessary.
  • The EVAP canister should be replaced
  • A new purge control solenoid may need to be installed

Related codes

A P0444 is related to and may be accompanied by the following codes:

P0440 – EVAP System

P0441 – EVAP System Incorrect Purge Flow

P0442 – EVAP System Leak detected (small leak)

P0443 – EVAP Purge Control Circuit Malfunction

P0446 – EVAP Vent Control Circuit Open or Shorted to Ground

Conclusion

In conclusion, the P0444 code is a diagnostic trouble code that refers to a problem with the evaporative emission system purge control valve circuit. The PCM detects an open circuit in the purge valve’s circuit and sets this code. Common causes for this code include disconnected or loose wiring harness, open circuit engine wiring harness, open circuit purge control solenoid, and defective PCM. Symptoms of a P0444 code are illuminated Check Engine Light, excess fuel vapors, and declining fuel efficiency.