VW Fox: Transmission Issues Point to Faulty Sensor

I had a similar transmission issue with my 2013 VW Polo diesel last year. Having some experience with basic car maintenance, I first suspected a transmission sensor problem, but it turned out the gearbox oil level was critically low, causing pressure issues. The symptoms matched yours exactly, transmission warning light, rough shifting, and occasional grinding. The oil pressure sensor was sending incorrect readings due to insufficient oil in the system. After getting it checked at my regular workshop, they discovered the low oil level was affecting the transmission pressure across the entire gearbox. The total repair cost was 365€, which included: Complete transmission oil flush, New transmission oil, Pressure sensor inspection, Labor costs Before we go further with suggestions, could you share: Current mileage on your Fox, When was the last transmission service, Do you notice any oil spots where you park, Does the grinding noise happen in specific gears This info would help determine if your issue is similar to what I experienced. Low transmission oil level can trigger various sensors and cause the symptoms you describe, but its best to verify the exact cause based on your specific situation.

Last service completed at 55000km and transmission oil was fine then. No oil spots visible under the car. The grinding noise mainly occurs when shifting from 2nd to 3rd gear, but the transmission warning light stays on constantly. The oil pressure sensor readings seem inconsistent according to the diagnostic report. Sometimes the transmission fault code appears and disappears on its own. Workshop quoted 480€ just to diagnose the exact issue with the transmission pressure system. The transmission issues started suddenly during normal driving conditions. Would rather avoid a complete transmission overhaul if the pressure switch is the actual problem.

Having gone through similar transmission issues on my VW Polo last year, I understand your concern about the repair costs. The symptoms you describe, especially the intermittent transmission fault codes and oil pressure sensor readings, strongly suggest a sensor-related problem rather than a mechanical failure. When I replaced my transmission oil pressure sensor, it resolved nearly identical issues. The inconsistent pressure readings and grinding between 2nd and 3rd gear match what I experienced. My workshop initially quoted a high diagnostic fee, but I insisted on checking the sensor first since it was the most likely and cost-effective fix. The sensor replacement on my car cost 220€ including parts and labor, significantly less than a full transmission repair. The grinding noise disappeared immediately after the new sensor was installed, and the transmission warning light hasnt returned since. Given your car has similar specs and the oil level was confirmed good at your last service, trying the sensor replacement first makes sense. Just ensure the workshop uses OEM parts for the pressure sensor to avoid future issues. If you want to verify before proceeding, ask them to check the transmission pressure readings at different gear positions while the engine is running. A faulty sensor will show erratic values compared to the factory specifications.

Thanks for the detailed feedback about the sensor replacement experience. The constant warning light and inconsistent error codes definitely point toward a sensor fault rather than mechanical damage. I will ask the workshop to specifically test the transmission pressure sensor first, since 220€ is much more reasonable than their quoted 480€ diagnostic fee. Will also request they monitor the transmission oil pressure readings across different gears during testing. The grinding noise being isolated to 2nd-3rd shifts suggests this could be sensor-related rather than a full transmission issue. Good tip about insisting on OEM parts for the pressure sensor, will make sure to specify that. If replacing the sensor fixes the problem like in your case, it would save a significant amount compared to transmission repairs. Will update once I get it checked and know if the transmission sensor was indeed causing these symptoms. At least now I have a clearer direction to pursue with the workshop rather than authorizing extensive diagnostic work upfront.