A4 1.8T Convertible, engine code BFB, year 2006, error code 16519

Hello forum members, the Audi mentioned above is displaying the following VCDS error code:
16519 Bank 1 Sensor 1 Heating Circuit P0135 008 - Intermittent electrical fault.

"The coolant temperature sensor has been replaced, and an oil change has been performed. The air filter and spark plugs have also been renewed. The Audi has 182,000 km on the odometer. When accelerating, the engine jerks, and it runs very poorly at idle when the A/C is turned on. My question to the experts is: how can I narrow down the cause of this problem? The exhaust system is leak-free. Can I check the oxygen sensor using VCDS, and if so, how? Or should I first inspect the vacuum hoses?"
I would be very grateful for your help. Have a good evening. Best regards, Wolfgang.

Hello, the oxygen sensor was okay, but the crankcase ventilation hose on the oil filter housing was defective.

Schmierpfote wrote:

Hallo, Lambdasonde war OK,KGE Schlauch am Ölfiltergehäuse war defekt.

Nice, but it's not causing any electrical faults.

Hello Rainer,
"I once took the Audi to a mechanic because the engine was running rough. Audi diagnosed the problem and replaced the ignition coils. However, even after clearing the error codes with VCDS, the engine still ran unevenly. I then replaced the crankcase ventilation hose and valve, and the Audi started running smoothly again. But after two years, the problems returned – this time it was a "lambda sensor" issue. The crankcase ventilation hose near the oil filter housing is not easy to see under the intake manifold. Anyway, it's working now. Have a good evening. Wolfgang."