VW Sharan Cold Start Issues Despite New Voltage Sensor

Had similar symptoms with a VW Touran 2013 diesel. The battery sensor replacement alone didnt solve the complete issue. After thorough battery testing and voltage measurements, it turned out the alternator wasnt providing consistent charge to the battery, despite the battery itself testing fine. The real fix required addressing multiple components: Cleaning corroded battery terminals and connections, Replacing the alternator due to failing voltage regulator, Updating the battery management system software Low voltage issues often point to charging system problems rather than just the battery sensor. In my case, the mechanics initial focus on just the sensor was insufficient. The alternator problem was causing the battery to receive inconsistent charge, leading to those slow morning starts and dim headlights. This was a significant repair that took proper diagnostic time to identify. The original battery sensor replacement masked the underlying alternator issue temporarily. Consider requesting a full charging system diagnosis including alternator output testing while the engine is running. If battery maintenance and testing show the battery is good, definitely push for checking the entire charging circuit. These symptoms typically indicate a deeper electrical system problem beyond just sensor issues.

Thanks for sharing that detailed experience. Very helpful to hear about the full charging system being involved, not just the sensor. Goes to show how vehicle diagnostics need to be thorough when dealing with electrical problems. My battery health issues were eventually sorted but took several visits. Curious, do you remember roughly how much the complete fix cost? And did the car behave properly after the repairs or did any low voltage symptoms return? Mine was producing similar symptoms again last week when it got cold, so Im wondering if I should look into the alternator too.

Thanks for asking about the costs. After getting the bad battery sensor fixed for 315€, my car has been running perfectly with no voltage issues, even during cold starts. The comprehensive vehicle diagnostics confirmed it was just the sensor causing problems, unlike my initial concerns about the alternator. Battery testing now shows consistent voltage readings across all conditions. What really made the difference was finding a mechanic who properly diagnosed the failing sensor instead of just checking basic battery charge levels. The previous attempts at fixing it had missed the subtle voltage fluctuations the faulty sensor was causing. If your car is showing similar symptoms again, definitely get the battery charge system checked, but dont automatically assume its the alternator. A proper diagnosis looking at voltage sensor readings while the engine is running could save you from unnecessary repairs.

Thanks for the advice. After bringing my car back to a different mechanic, they ran a complete battery maintenance check and found the issue was more complex than initially thought. The new shop did a proper vehicle diagnostics scan that showed the alternator was actually fine, but found a damaged wiring harness affecting the charging system. The total repair came to 280€ including labor, much less than I feared for an alternator replacement. The low voltage problems completely disappeared after fixing the wiring. No more slow starts or dim headlights, even in cold weather. Battery testing now shows consistent charge levels. Really glad I got a second opinion and proper diagnostic work rather than just throwing parts at the problem. Goes to show the importance of finding a mechanic who takes the time to thoroughly check battery health and charging systems rather than making assumptions. My car starts perfectly now, even on the coldest mornings.