98 civic cx, code p0135

ive had an intermittent check engine light for the past couple weeks. every
time, its the same code- P 0135. reset it once, went away for 2 days, reset
it again, went away for a week. now it goes on every time i reset it.

according to the scantool, its sensor1, bank1, heated O2 sensor heater
circuit malfunction.

my questions:

is this normal for a car with 45k miles?

is this the lower sensor, below the cat? the lower one is a 4 wire sensor,
the upper one is a 3 wire sensor. i would guess the 4th wire is the "heater"
part.

could it be *anything* else? the engine bay is clean, all wires look good.
ive heard about a possible issue with the O2 wires rubbing against a
bracket, but didnt see anything that looked out of place.

would it be worth it to take it to a dealer, in case its a wiring issue and
a new sensor doesnt cure the problem? id hate to buy a nonrefundable O2
sensor, and have the problem reoccur.

any decent place i can buy the sensor, aside from the dealer? ive heard good
and bad about bosch, but some pretty good stuff about napa, and theres a
napa down the street. i already know the dealer would bend me over if i
bought one through them. how about online dealers?

 

read your warranty manual, I think you have 80k miles warranty on emission
components including O2 sensor; if so dealer will replace it for free
please let us know if that's correct

 

8-80 only applies to a couple of things. should be 3-36 on o2's. i
don't remember which car the wiring issue was on but the harness under
the intake manifold would rub on the intake support bracket, and set
several codes.
replace the sensor.it's the upper one
Chip

 

done. neither napa, autozone or kragen had the $90 bosch sensor in stock, so
i got one at the dealer for $200. sucks, but hey- its the first unscheduled
repair ive had to do on it in 6 years.

 

its the one before the cat. is this normal for a car with 45k miles? yes.
and I hope your not resetting the light my disconnecting the battery, that
wont work.

 

kinda figured it would last longer than that

i got the scantool. i like it!