Jetta Hybrid Starting Issues, Sudden Power Loss Fix

As someone with moderate experience working on hybrids, I dealt with a very similar issue on my 2016 Passat Hybrid. The symptoms were nearly identical, dashboard lights would come on when turning the key, but the engine would either fail to start or run very roughly. After some diagnostic work, my workshop found a blown fuse connected to the ignition coil circuit. The car electronics were getting power, but the ignition system wasnt functioning properly due to this simple issue. The total repair cost was 52€, which covered the fuse replacement and diagnostic time. It could definitely be related to your ignition coil or fuse system, given the symptoms you describe. However, to help narrow down the exact cause, could you share: Does the check engine light come on? Are there any unusual sounds when you turn the key? Have you noticed any other electrical issues recently? How many miles/kilometers are on your vehicle? A faulty ignition switch would typically show different symptoms, like complete electrical failure or key turning issues. Since your starter motor sounds normal, I suspect its more likely related to the ignition system components or fuses. Consider having a professional check the fuses and ignition coil first, as these are common failure points in these models and relatively inexpensive to diagnose.

Last service was done at 65000km and the issue started shortly after. Just had the fuses checked today and all of them tested fine. The check engine light does come on intermittently when the problem occurs. The starter motor turns normally but the engine struggles to catch. No other electrical issues noted and the key turns smoothly in the ignition switch. Considering the unreliable starting and rough running, could it be related to the fuel delivery system? The symptoms seem different from a typical ignition switch failure since all electrics work fine when turning the key.

Thanks for the additional details about your Jetta Hybrid. After my own experience with the fuse issue on my Passat, I explored several other potential causes when the problem returned months later. In my case, it turned out to be a failing fuel pump rather than the ignition switch. The symptoms perfectly match what youre describing, normal key turn function, good fuses, intermittent check engine light, and rough running when the engine does start. The fuel pump began failing gradually, causing: Inconsistent fuel pressure, Hard starting, Unusual engine stalling, Rough running The repair cost was 480€ for parts and labor. Since then, the car has run perfectly with no starting issues or engine performance problems. Given your symptoms and the fact that fuses checked out okay, I suggest having the fuel pressure tested. The fuel pump is a common failure point on these models around 60000-70000km. This would explain why the engine struggles to catch even though the starter motor and car electronics are working normally. While a faulty ignition switch can cause similar issues, the fact that your key turns smoothly and all electrical systems work properly points more toward a fuel delivery problem in this case.

Thanks for the detailed follow up. Based on my recent service records and mileage, this fuel pump theory makes a lot of sense. The timing matches since my issues started around 65000km, very close to what you experienced. I will get the fuel pressure tested rather than focus on the ignition switch. Your symptoms sound identical to mine, especially the combination of hard starting and unusual stalling even though the starter motor and electrics work fine. The 480€ repair cost is helpful to know for budgeting. Much better than continuing to chase electrical gremlins or replacing parts unnecessarily. Will schedule a fuel pressure test this week and update once I know more.