Hello, I have a problem with my Volvo. The ABS and TRACS lamps light up permanently. We soldered and tested the control unit. All 4 sensors are now new. At the last read out (after installation of the control unit) it shows the error sensor at the front left and back right. At the back right it was possible to delete, but not at the front left. Just changed the sensor at the front (the old one had the same resistance values), but the lamps are always on. djemand can help me. Achso car is: Volvo 850 Built. 12/95 170 HP / Petrol / 20V Greeting Horst