VW Polo Diesel Stalling Issue: IAC Valve Fault Alert

Had exactly this issue on a 2016 VW Golf TDI. The symptoms match perfectly, engine stalling at idle and erratic idle speed when stopping at lights. The IAC valve was indeed the culprit, along with heavy carbon buildup in the intake manifold. These diesel engines are prone to intake contamination, which directly affects the idle control system. The throttle body and IAC valve work together to maintain proper idle speed, but when contaminated they cant regulate airflow correctly. The repair involved removing and cleaning the IAC valve, plus a thorough intake cleaning service. This was definitely not a quick fix, required specialized equipment and several hours of labor to properly clean all components. Engine stalling issues stopped completely after the service. Worth getting a second opinion, but these symptoms strongly point to IAC valve issues. Left untreated, it can lead to more serious problems like damaged sensors or complete engine stalling while driving. The fact your Polo is showing these signs at 68000km is quite typical for this engine family. Suggest having both the IAC valve and intake system inspected, not just a basic diagnostic scan.

Thanks for sharing your experience with the Golf. My Polo started showing similar issues last month, rough idle and stalling when stopping. The IAC valve replacement and intake cleaning fixed it completely. Did the engine idle problems come back at all since your repair? Would be good to know the approximate cost too, as prices seem to vary quite a bit between shops. My local mechanic quoted almost double what others charge for air intake system work.

The engine stalling and idle speed issues never returned after getting the IAC valve replaced and intake system cleaned. Its been running smoothly for over 18 months now, with stable idle and no check engine lights. The total cost was 425€ for the complete service, which included cleaning the heavily contaminated intake and replacing the faulty idle air control valve. This price seems fair given the amount of labor involved in properly cleaning all the components. Some shops charge more because the intake cleaning requires specialized equipment and expertise, especially on these diesel engines. The throttle body and surrounding components were also quite dirty, which was contributing to the irregular idle. Making sure all these parts were properly cleaned was key to solving the problem permanently. If you notice any idle speed fluctuations in the future, best to have it checked early before it leads to complete engine stalling again.

Here's my story after dealing with this idle control issue. Finally took it to a reputable diesel specialist after getting tired of the constant engine stalling. They properly diagnosed the idle air control valve issue and found significant carbon buildup in the intake. The whole job took about 4 hours, they thoroughly cleaned the intake system and replaced the IAC valve. Total bill came to 380€, which was much more reasonable than the 650€ quoted by my regular mechanic. Car runs perfectly now with stable idle speed and no more stalling when stopping. Best decision was getting that second opinion. The specialist showed me all the contaminated parts they removed and explained how the carbon buildup was affecting the idle control. Three months later and the engine still idles smoothly with no check engine lights or stalling issues. Running costs are actually lower now too since the engine isnt fighting against all that carbon buildup. Should have done this repair much sooner instead of putting up with the constant stalling.