VW Golf Hybrid Engine Issues Linked to Water Sensor

As someone with some hands-on experience working on hybrids, I dealt with a similar sensor fault on my 2016 VW Passat GTE. The symptoms were nearly identical, malfunction light and rough running engine. A car diagnostics scan initially pointed to the water sensor, but the actual issue turned out to be much simpler. The workshop found a damaged wire connection to the sensor unit. The cable insulation had worn through, causing intermittent electrical faults and false readings. The fix involved repairing the wiring harness and properly securing the connection, total cost was 95€ including diagnostics. Since the repair, no more sensor issues or warning lights. Before jumping to sensor replacement, you should have the wiring and connectors thoroughly checked. Auto electronics issues often stem from connection problems rather than failed sensors. To provide more specific guidance: What error code is stored in the fault memory? Have you noticed any coolant loss? Does the problem occur more during cold starts or when the engine is warm? Are there any other warning lights besides the malfunction indicator?

Last service was at 98000km. The error code shows P0116 which points to a sensor malfunction. My moisture sensor seems fine but there could be a hidden electrical fault somewhere in the system. The problem mainly happens during cold weather after the car sits overnight. No coolant loss noticed and temp gauge reads normal. Only the malfunction light comes on. After reading about similar sensor issues, I am leaning toward having all connections checked first rather than replacing parts right away. The auto electronics in these hybrids can be tricky, so systematic troubleshooting seems like the smart approach. Looking at a shop visit next week to get a proper diagnosis of the sensor readings and electrical connections.

Thanks for the additional details. Your P0116 code and symptoms match exactly what I experienced with my Passat GTE. The cold weather correlation is particularly telling, this is when moisture sensor and electrical issues tend to show up most. The normal coolant level and temperature readings are good signs. In my case, the sensor itself was reading correctly, but corroded terminals in the wiring harness caused intermittent electrical faults during cold starts. Moisture had gotten into the connection, leading to unreliable sensor signals. Since your symptoms mirror my experience so closely, I strongly suggest having the workshop focus on: Checking connector terminals for corrosion, Testing wiring continuity in cold conditions, Inspecting harness routing for any wear points, Verifying sensor ground connections The systematic approach you are planning is smart. My repair ended up being straightforward once the actual fault point was found. Just cleaning and resealing the connections resolved the sensor issue completely. One tip: Ask the workshop to perform the checks with the engine both cold and at operating temperature. This helped identify the exact conditions triggering the fault in my case.

The systematic troubleshooting approach makes perfect sense based on your experience. Good to know the P0116 code and cold weather symptoms matched your situation. I will definitely have them check all those connection points you mentioned, especially since corrosion in the wiring harness seems to be a common culprit with these sensor faults. The car sensor readings being normal except during cold starts does suggest an electrical issue rather than a failed component. I will ask them to test thoroughly under both cold and warm conditions as you suggested. The malfunction indicator coming on mainly after sitting overnight fits with potential moisture-related connection problems. I feel much better prepared now knowing what to request at the workshop. Will focus first on having them inspect the wiring, connectors and grounds before considering any sensor replacements. Thanks for sharing your repair experience, it has really helped narrow down where to look for the fault. I will update once I get the diagnosis results next week.