VW Atlas Won't Start, Dead Silence Points to ECU Issue

Having some experience with VW models, I had a very similar issue with my 2019 VW Tiguan. Initially thought it was an ECU failure too, but it turned out to be much simpler. The check engine light appeared briefly, just like in your case, and the car would not start. After a thorough inspection, the workshop found corroded battery terminals and loose connections. This was causing intermittent power delivery issues to the engine management system. The fix included: Cleaning both battery terminals, Replacing damaged cable connectors, Properly securing all connections, Clearing engine fault codes from the system Total cost was 155€ for parts and labor. The whole repair took about an hour. Before suggesting more specific solutions, could you share: Does the battery warning light illuminate when you turn the key? Have you noticed any electrical issues before this happened? When was the last time the battery was replaced? Are there any other warning lights showing up? Engine stalling or starting issues can have multiple causes, and having these details would help narrow down if your problem matches what I experienced with my Tiguan.

Thanks for the input. Latest service was at 90000km and the issue started shortly after. After reading your response, I checked the battery terminals and connections, all look clean and tight. Also tested the battery voltage which reads 12.8V. Engine fault codes were cleared during the last service just 3500km ago. The battery warning light does not come on at all when turning the key, which seems different from your case. No electrical issues before this, and the battery is the original one from 2021. The check engine light only flashed briefly before the no-start condition and hasnt reappeared since. Would it still be worth checking the battery connections again, or should I be looking at other potential causes for the engine software or starter system?

Based on what you described, this seems different from my Tiguan situation, even though the initial symptoms appeared similar. With both cars being VW and fairly recent models, I understand our first thought about an engine software or ECU failure. Since your battery tests good and connections are clean, we should look at other components. When my Tiguan had a follow-up issue months later, it turned out to be the starter relay, a common failure point that can cause similar no-crank situations without triggering constant warning lights. The engine fault codes being cleared recently and the brief check engine light suggest a possible intermittent sensor issue. In my case, this happened with: Faulty crankshaft position sensor, Damaged wiring harness near the transmission, Starter relay connection issues The repair costs varied: Sensor replacement: 180€, Relay replacement: 85€, Wiring repair: 250€ Since you mentioned the recent service, check if any work was done near the engine wiring harness. Sometimes disturbed connections can cause an engine surge or starting issues weeks later. Would recommend having the starter circuit tested first, its usually less expensive than diving into ECU diagnostics, and matches the symptoms you described.

Thanks everyone for the suggestions. After considering your feedback, I'm leaning toward having them check the starter circuit and sensors first before jumping to ECU diagnostics. The fact that there's no clicking sound when turning the key definitely points more toward a starter system issue than a fuel injection or general engine software problem. What's interesting is how the check engine light only flashed briefly, very similar to what happened with your Tiguan's crankshaft sensor issue. I'll make sure to mention these specific symptoms when I drop it off, especially the complete silence when trying to start and the fact that the battery and connections all checked out fine. I feel better prepared now for the diagnostic process, and it's helpful knowing the potential repair costs. Will post an update once I get the actual diagnosis and repair completed. Really hoping it's just a starter relay or sensor rather than a more complex ECU issue.