Hello, I drive a VW Touran 1.4TSI BJ. 2009 and have the following problem: approx. all 100km the engine control light appears. I have an OBD2 Bluetooth Adater and this one reports the error P0420 (Efficiency KAT). I wanted to have the error fixed in a VW workshop, however the VW workshop does not come to the ECU. We had the same error already last year on the way on the holiday. Engine control light came during the ride and VW could not get the ECU out a test with a control unit from another Touran had shown that the reading is possible in principle. I was then recommended to replace the engine control unit. I had done this, but I had to get the control unit used myself, because these were not available at the time and we were stuck in the middle of Germany on the way to the holiday. After the installation of the new control unit, we were able to find the correct control unit. The error (sensor in the tank cover) could be found and repaired. The current reported error (a lack of Kat-Efficiency) came for the first time a few weeks ago. After consultation with a well-known mechanic I had deleted it and drove to the already due TÜV. The car passed the exhaust gas examination without complaint. The VW workshop now wants to open the complete cable harness and measure it (>200€). I fear that it again on the Does anyone have an idea?