This might help you.
http://www.obd-codes.com/p0134
Have you checked the heater circuit? At the O2 connector the black wire is the ground. You should have 5 ohms or less to ground. The dark green with orange tracer wire is the voltage supply for the heater. You should have battery voltage with key on. If you don't have DMM you can use a simple test light. Test light is better in some instances because you are putting some load on the circuit.