P1135 in '99

My '99 is throwing code P1135, Heated O2 sensor bank 1 sensor input low. I've been googling to find more, but so far found mostly others with the
same question, and not more information. It is a CA car, which complicates things a bit. So is this an O2 or A/F sensor? Anyone know of a definitive source for a replacement? Seems like I could DIY, if I could find the correct part.
Is there a good reference book for the 99's? Even the online parts manuals from mazda seem to skip over the O2 sensors (or perhaps I'm just not find them).
thanks,
--
John F. Detke | "Where dat mommy go?"
snipped-for-privacy@panix.com | -- James, age 2 when his mom
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
The front O2 sensor is reported as bad. (Low output) If you are willing to replace it yourself, and don't mind using a Bosch sensor that requires that you use a splicer supplied with the sensor, you can save a bunch of money. Cost is about 70-80 $ instead of about 250 for the dealer supplied Mazda P/N sensor with the Mazda plug on it. Guess the plug is expensive. The front sensor has a shorter life than the rear sensor, since it gets exposed to the hot raw exhaust gasses from the engine.
| -- James, age 2 when his mom
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.