how can i fix my opel vectra abs and traction light both on?

The Opel Vectra 2.0 model 2001 I use in the Philippines has both the ABS and Traction Control lights on and the speedometer not working. We interchanged both input and output speed sensors and they are both ok. We tried replacing the electronic box under the glove box with an okay one and the lights were still on. My mechanic soldered a few connections on the ABS module but the lights are still on. He said the solenoid might be dirty and will return to fix it. On a cold engine, it takes about 10 kms of travelling before the problem occurs. When it does, the engine is always running on low gear. What seems to be the problem? Thanks