You may want to check the sensor plug and connections before changing that sensor.

Under the passengers rug is the 02 Sensor connector plugs.. [ 2 of them...a single wire and a 3 wire..side by side...total of 4 wires]
This is a 4 wire/single sensor [ two wires for the sensor output to the ECU , and two 12v supply wires for the sensors heater circuit.]
One plug has 3 wires .. This is Connector G3/2x1 on the wiring schematic for your chassis. [ which shows single sensor only] ...the terminal numbers on that plug are 1/2/3... with 1 and 2 being the heater circuit, and # 3 being the ground for the 02 signal. Then there is a single plug [ green wire ]..that is the 02 Sig wire for the sig to the ECU.
[ anyone following this with Factory CD, this is engine wiring schematic 07-2.00/1-93/95 HFM/SFI W/104. Page 1....note single sensor G3/2]
You want to check that both these connectors are fully plugged in and the wires are not worn from passenger traffic, etc. If all looks good there , here is the heater circuit test procedure:
I would unplug the 3 wire connector and check across the 1 and 2 wires going to the 02 [ tru the floor] with an ohm meter...that will tell you if the heater is faulty/open on the 02 sensor ...that is a highly probable b/c of the code and a bad heater would also pop an AIR code b/c the sensor does not retain enough heat w/o the heater circuit to attain the max lean reading the ECU is looking for with the AIR activation self test. Heater amp draw spec is 1.2-2.2 amps. That equates to approx. 6-10 ohms.
If this is something you are not comfortable with, print it and give it to your mechanic, [ in the event he is not familiar w/this system].
If the heater ohms out as OK/Good, then you can turn the key ON and see if you have 12v at the feed side of the connector [ same 1 and 2 ] going to the heater in the 02 sensor. * Polarity Note --- terminal 1 is +pos.12v and 2 is -neg. 12v. That is the complete heater circuit test for 02.
If no ohms or incorrect ohms on heater, change the 02 .
An actual 02 sensor closed loop sig test for ECU can be gotten from the green/single wire connector. He will know that.

__________________
A Dalton