O2 Sensor, One or Two on 99 Civic LX?

My daughter has a 99 Civic LX, California Model (LEV I think)?

Does this car have one or two O2 sensors?

She got a CEL, Autozone says their scanner cannot differentiate between
a front or a rear O2 sensor failure.

The front sesnor is about a year old.

Are there front and rear sensors, or is the Auto Zone dude all wet?

The rear sensor price is about $250 (if there is such a thing).

Tom

 

I don't know if it has one or two, but if the new front sensor is an
aftermarket unit and not OEM, it could pose problems.

 

Most Hondas on the USDM market has two O2 sensors after 1995. This is
where they introduced OBD2 - and a secondary O2 is part of the OBD2
system. It is located in the end of the CAT - and all it really does is
to check that the CAT is working ok. It may be replaced with an O2
simulator - approx 100 usd.

 

Most Hondas on the USDM market has two O2 sensors after 1995. This is
where they introduced OBD2 - and a secondary O2 is part of the OBD2
system. It is located in the end of the CAT - and all it really does is
to check that the CAT is working ok. It may be replaced with an O2
simulator - approx 100 usd.

 

All OBDII cars have at least 2 O2 sensors. Take it to a service shop or
dealer who can test them as throwing parts at it will get very expensive....

 

There are front and rear sensors. You can go to Majestic's site
http://www.hondaautomotiveparts.com/ , put in the car's info, pull up the
exhaust manifold drawing, and see their location. The front one goes for
about $155 + s/h. The rear goes for about $194 + s/h.

Here's a nice summary description of what each does:
http://www.samarins.com/glossary/oxygen_sensor.html

IIRC, if the rear one fails, you risk destroying the catalytic converter,
which is expensive.

If the front one has failed, you should be seeing other symptoms, like poor
mileage, irregular RPM, hesitation, etc.

 

2. one staring you right in the face on the exhaust manifold, and one
after the cat, which is bolted to the exhaust manifold.

they need a new scanner then. IIRC, my code was PO135 primary oxygen
sensor heater circuit malfunction.

primary means top, the sensor in the manifold.

OEM honda, or aftermarket? either way its worth testing the sensor for
continuity. for me, the 2 bottom black wires read 0 ohms, which meant
the heater circuit was dead. or something like that. id bust out the
ohmmeter and helm manual and test em both.

yep, there are. but front=top and rear=bottom

 

Thanks all for the good advice. The converter is a good bit closer to
the engine than I thought it would be. I'll get an updated code and
figure out which sensor is the problem.

2nd problem. The hood latch handle broke off in my hand. Did they get
this part from GM?

Tom

 

My hood latch handle on my 98 Civic also broke. I've become quite adapt at
gripping the leftovers with my thumb and index finger and if that fails,
I've got a little pliers in the door bin.

Pars