Hello together. I have the following problem: My 170er no longer starts and the fuel pump is no longer controlled. I now found out that my fuel pump relay is sitting in the relay module unit K40 (motor room passenger side of the OBD plug). Have already read some threads to the part and on which pins it is now. Just don’t bring me much if I don’t know exactly how to check a relay. Here a short pin-set of the supposed plug: PI N 1 = terminal 30 (duration+) for relay fuel pump, vein colour red (2.5mm2) PIN 2 = unused PIN 3 = 12V+ for fuel pump, vein colour red/grey (2.5mm2) PIN 4 = terminal 30 (duration+) for , vein colour red (2.5mm2) PIN 5 = mass The 15A fuse that secures the pump is usually required for help !