my 1999 civic has CEL, I checked the code, it's #41. Primary oxygen sensor heater circuit malfunction.
My questions:
1. do I need change a oxygen sensor or I need let workshop fix the heater?
2. how do I identify the heater inside the sensor has problem or the heater circuit has problem, like check the heater fuse all right
3. if I need change the sensor(for example the heater head has problem, becuase the heater is inside the sensor, I have to change whole sensor). which one sensor is primary sensor? I can see two sensor made by Denso, one is on top of exhaust pipes another one is on bottom of exhaust pipes. How to check which one has problem?

Thanks for any useful suggession. if you have new idea or new clue, pls let me know.

 

secondary is after the cat, primary before.

at least on a 00... the primary should just have a keyed adapter, the secondary has wires that run up into the floorboard.

 

I use same model with you, 2000 civic EX, only different is my car is 4-door.

 

your primary one is on the header.....and i had this problem before also, just replace it with another 02 sensor and the should fix the problem

 

Sorry, what do you mean "02 sensor". Civic 2002 model's sensor?
Thanks!

 

oops, silly me, you mean "another O2 sensor" got it
Where to buy? which brand is good? My current one on my car is Denso, I checked ebay, expensive than others.
Any recommendation?

 

i would recommend another denso 02 sensor because its straight plug and play and all those other other one's u have to wire it so i would go for the denso one

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by aeoluss &raquo;</TD></TR><TR><TD CLASS="quote">which brand is good?</TD></TR></TABLE>

Denso or NTK. Bosch sucks.

 

Where do you think is good place to buy? From pepboy? or buy it online(Ebay)?
What's your experience on compare quality and price?
Thanks!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by aeoluss &raquo;</TD></TR><TR><TD CLASS="quote">Where do you think is good place to buy? From pepboy? or buy it online(Ebay)?
What's your experience on compare quality and price?
Thanks!</TD></TR></TABLE>

Honestly wherever you can get it cheapest is probably fine. I bought my last one from a local independant parts place in town. Denso and NTK are pretty similar quality wise, but denso is the original OEM supplier for honda so its somewhat preferable, NTK seems to be just as good or almost as good though. Just stay away from bosch.

 

i just checked my bulbs in my cluster and the CEL light was broken and im throwin code 41 also....could this make it so im getting bad gas mileage too? i also have code 16 but its because i have dsm 450's