ABS light on

In my 2004 Cavalier 2.2 ecotec, the Abs light is on. Code says faulty front left abs sensor reading. I replaced the abs sensor, reset the code and it worked for about 1 minute. We monitored the readings from the abs sensor on a handheld computer.

What I've done

1. Scanned code, code said it wasn't reading the information from the abs sensor.
2. Replaced sensor and reset code.
3. Checked wires from the front left sensor, the faulty one, to the main bundle of wires. Found no faults except for the possible ground.