Definition:
This diagnostic trouble code (DTC) indicates that the powertrain control module (PCM) has detected an issue with the evaporative emission control system (EVAP) purge flow. The purge flow is the process of drawing fuel vapors from the charcoal canister (also known as an evaporative canister) and introducing them into the engine to be burned.
Causes:
* Faulty Purge Valve: The purge valve is responsible for controlling the flow of fuel vapors from the canister to the engine. A stuck open or closed purge valve can cause this code.
* Clogged Purge Valve Line: The line that connects the purge valve to the canister can become clogged with debris or condensation, restricting the flow of fuel vapors.
* Faulty Charcoal Canister: The canister can become saturated or damaged, preventing it from properly storing fuel vapors.
* Vacuum Leak: A vacuum leak in the EVAP system can affect the purge flow, leading to the code.
* Faulty PCM: In rare cases, a malfunctioning PCM can cause the code.
Symptoms:
* Check Engine Light: The illuminated check engine light is the most common symptom.
* Reduced Fuel Economy: A malfunctioning EVAP system can lead to increased fuel consumption.
* Strong Fuel Odor: Fuel vapors may be released into the atmosphere if the system is not working properly.
* Rough Idle or Stalling: In extreme cases, a severe EVAP leak can cause engine problems.
Troubleshooting Steps:
1. Inspect the Purge Valve: Check the purge valve for proper operation. Test its electrical continuity and make sure it opens and closes when commanded by the PCM.
2. Inspect the Purge Valve Line: Check the line for any blockages or leaks.
3. Inspect the Charcoal Canister: Make sure the canister is not saturated or damaged.
4. Check for Vacuum Leaks: Inspect all components of the EVAP system for any leaks.
5. Inspect the PCM: If all other components have been ruled out, the PCM may need to be checked.
Note: It's important to consult a repair manual or a qualified technician for accurate diagnosis and repair.
