VX code 48 on deceleration -> Replace LAF O2 sensor?

[Carwhisperer]

I have a turbo'd vx motor in an AWD obd0 chassis. 49 state P07, LAF. I get about 31 mpg when I drive half time at 80 mph and 35 or so if I stay around 62 mph (80 mile round trip commute, 4000ft elevation to sea level). I get code 48 and 12, I think the CEL is set more by 48 than 12. If I turn the key off and on the CEL goes off. When the CEL is set does the car go into open loop? Also, the CEL comes on most during deceleration. Is this likely a bad LAF sensor?

[SVOboy]

Sounds like the LAF is toast. Especially considering what I would consider terrible mileage with that car. When I had a bad LAF in my crx-vx I still managed high 40s without effort, so that'd be my only guess.

[slogfilet]

There's gotta be a post about it around here, but is the VX O2 sensor generally "good" or "bad" with little in between. or does it gradually deteriorate?

If I am able to test it with my voltmeter, will the results give me the general health of the sensor, or just whether or not it will throw a code?

Sorry for the semi-hijack... hope this helps you as well!