VW Touran Purge Valve Causing Stalling and Rough Idle

I had a similar issue with my VW Golf 2016 and can share my experience with the check engine light and emission system problems. I have some experience working on VAG cars and maintaining them. The symptoms you describe match exactly what I encountered, rough idle and stalling, especially with low fuel. My workshop diagnosed it as clogged hoses in the EVAP system rather than just the purge valve. The tank ventilation system gets gunked up over time, restricting proper fuel vapor flow. The full diagnostic process included: Pressure testing the EVAP system, Checking all vacuum lines for leaks, Testing the purge valve operation, Inspecting charcoal canister condition Total repair cost was 175€ which covered cleaning out the hoses and testing the system to ensure proper operation. The rough running completely disappeared after the fix. To help troubleshoot your specific case, could you share: Current mileage on your Touran, What type of fuel you typically use, Whether you notice any fuel smell, If the check engine light is steady or flashing These details would help determine if you are dealing with the same root cause or potentially different emission system issues.

After taking it to the workshop last week (109036km), I can confirm it was related to a faulty pressure sensor in the EVAP system. The rough idle and stalling issues started showing up intermittently, particularly when the fuel tank was low, but the mechanics found the sensor was sending incorrect readings to the ECU. The diagnosis showed the purge valve was actually working fine, but the faulty sensor was causing the system to operate erratically. Total repair came to 220€ including diagnostics. The check engine light has stayed off since the fix and the car runs smoothly again. Make sure your workshop does a complete EVAP system test rather than just replacing parts. A proper diagnostic scan can save time and money by pinpointing the exact issue.

Thanks for the update on your Touran's repair. It is interesting how similar our emission system issues were, yet the root cause was different. On my Golf, the clogged EVAP lines were the culprit, while your case involved the pressure sensor. The way these tank ventilation systems work, multiple components can cause similar symptoms. When my check engine light first came on, I also suspected the sensor but was surprised to find it was actually the blocked lines causing incorrect readings. Since the repair, I have made it a habit to avoid running the fuel tank too low, as this seems to put extra stress on the EVAP system components. Have you noticed any difference in how your car runs now with different fuel levels? One tip that worked for me: using high-quality fuel seems to reduce deposit buildup in the emission system. After 30000km since my repair, I have not had any recurring issues with the check engine light or rough idle. Good to hear your car is running properly again. These diagnostic-first approaches definitely save money compared to just replacing parts out of nowhere.

Thanks for following up regarding my Touran EVAP system issue. You are right about the similarities in our problems, though yours turned out to be clogged lines while mine was the pressure sensor. Since the repair, I have noticed the car runs consistently well regardless of fuel level. Previously, it would definitely struggle more when the tank got below a quarter full. The emission system seems to be working as designed now that the sensor is providing accurate readings to the ECU. I appreciate the tip about fuel quality. The mechanic mentioned the same thing, that premium fuel can help prevent deposit buildup in the EVAP system components. I have switched to higher grade fuel and plan to maintain at least a quarter tank to reduce strain on the system. The 220€ spent on proper diagnostics and repair was worth it rather than guessing and replacing parts. For anyone else facing similar check engine light and rough idle issues, having the complete EVAP system tested is the way to go. My specific case shows that even when symptoms point to one component, like the purge valve, the actual problem could be a different part of the emission system.