Volkswagen 01795 Trouble Code

[JourneyLynn]

Volkswagen 01795 trouble code (brake vacuum system malfunction). Check the brake fluid and vacuum pressure sensor faults. During normal operation of the brake system, the vacuum pump maintains the vacuum pressure between 50~70kPa. When the brake pedal is pressed, it causes a decrease in vacuum pressure in the vacuum lines (increase in absolute pressure). Upon receiving the signal from the vacuum pressure sensor, the system determines if this pressure is outside the maintenance range and automatically activates the vacuum pump. At this time, you can hear the "humming" sound of the vacuum pump operating, which stops after about 3 seconds when the vacuum reaches the set value. If not, it can be preliminarily judged that the system is not working properly. After the brake vacuum pump operates for 5 minutes (repeatedly pressing the brake pedal until the vacuum pump runs continuously several times), check for any abnormal noises or odors from the vacuum pump, and inspect whether the vacuum pump controller and connecting wires are deformed or overheating. If the vacuum pump produces abnormal noises or odors, it may be caused by severe internal wear of the vacuum pump.

[AllieRose]

The fault code 01795 in Volkswagen vehicles actually relates to the sunlight sensor signal issue. I've encountered many car owners visiting repair shops due to this code, when in fact it's simply caused by obstruction of the small black dots under the windshield. This sensor controls automatic headlights and air conditioning temperature regulation - for instance, it detects sunlight intensity in summer to make the AC blow cooler air. Common causes include: metalized window tint blocking the signal, loose sensor connector, or foggy windshield affecting readings during rainy days. Once a friend placed a reflective picnic mat on the roof, triggering the 01795 code on the dashboard immediately, which disappeared after removing the mat. The sensor itself rarely fails - try cleaning the sensor area with a damp cloth first before further troubleshooting.

[Gordon]

I've studied the 01795 code for a while. Essentially, it means the in-car sunlight sensor doesn't match the actual light intensity. This not only affects the automatic headlights but also messes with the climate control - you might get blasted with hot air on a sunny day. Focus on checking the small dot near the rearview mirror base on the windshield interior to see if it's blocked by parking permits. The most ridiculous case I've seen was when a dealership covered half the sensor while applying the annual inspection sticker. Also, older cars need to watch out for wiring issues - I encountered a 10-year-old Tiguan that kept throwing 01795 codes due to aged wiring between the sensor and AC control panel, which was fixed by rewiring.