Flashing CEL and Rough Idle on VW Touran, Throttle Issues

A similar issue occurred on my 2015 VW Tiguan with the 2.0 TSI engine. The symptoms matched exactly, unstable idle problems and engine stalling, particularly noticeable when the engine was warm. The cause turned out to be a vacuum leak where the brake booster hose connects to the intake manifold. This affected the air supply system and threw off the air-fuel mixture. The throttle body was initially suspected, but inspection revealed the deteriorated hose was the root cause. The repair involved replacing the cracked vacuum line and checking all connected components. This is considered a moderate repair as vacuum leaks can lead to more serious engine performance issues if left unaddressed. The diagnostic process required a smoke test to pinpoint the exact location of the leak. Most reputable shops should be able to diagnose this fairly quickly with the right equipment. Key warning signs that confirm this diagnosis include: Uneven idle speed, Engine stalling or rough running, Hissing sounds from the engine bay, Decreased brake pedal assistance Getting this fixed promptly is important as continued vacuum leaks can cause additional engine management problems over time.

Thanks for sharing that detailed experience with the vacuum hoses. I had almost identical symptoms on my Touran last winter. The check engine light started flashing and the engine would stall at idle. The throttle body seemed to be the obvious culprit at first. Would you mind sharing what the total repair cost was in your case? My fix ended up being surprisingly reasonable but curious how it compares. Also wondering if youve had any recurring issues since getting it sorted? My engine has been running smoothly after the repair but always good to know what to watch out for.

Glad to provide an update on my vacuum hose repair experience. After seeing the mechanic, they confirmed the air valve issue was indeed causing the idle problems. The root cause was a faulty hose connection from the pump to the valve, which was allowing air to leak and disrupting proper air intake flow. The total repair cost came to 175€, which included parts and labor. Looking back, this was quite reasonable considering the diagnostic work needed to pinpoint the exact location of the vacuum leak. Since the repair, my engine has been running perfectly with no check engine lights or idle issues. The throttle response is noticeably smoother, and the engine maintains a steady idle just like it should. I check the vacuum hoses periodically now during routine maintenance, but havent had any recurring problems in the past 8 months. Regular inspection of the air intake system components is always good practice to catch any potential issues early. The original symptoms completely resolved once the proper repair was done.

Finally got my car sorted! Took it to a local mechanic who specializes in VW repairs. The check engine warning turned out to be exactly what was suggested, a vacuum leak from a cracked hose near the intake manifold. The repair bill came to 190€ total. Bit more than expected but included a full diagnostic check and replacement of two worn vacuum hoses they found during inspection. The air intake system got a thorough cleaning too while they were at it. Engine runs perfectly now, no more stalling or rough idle issues. The mechanic showed me the damaged hoses and explained how they affect engine performance. Really glad I didnt ignore those early warning signs. Definitely learned my lesson about getting strange engine behavior checked out promptly. Been about 2 months since the fix and no issues at all. Feel much better knowing the problem was caught before it could cause any serious engine damage. Thanks again for pointing me in the right direction with the diagnosis.