Leliel

Thought I'd try my hand at writing a DIY for the basic sensor replacement I did a couple months ago. For my fellow n00bs.

First of all, be aware that the Hybrid, unlike other 4-cyl 7th gen Civics, has two catalytic converters in series and therefore three Oxygen (O2) sensors overall. A primary (not covered here), a secondary and a tertiary. For a single-cat Civic just ignore everything to do with the tertiary sensor below.



WHAT YOU WILL NEED:

1. O2 sensors -secondary and tertiary. You want to replace these at the same time.

Do yourself a favor, call your local dealership and order OEM Honda O2 sensors. Pricey, yes, but less so than finding out the hard way that the ones AutoZone will sell you a) won't clear that malfunction indicator lamp and b) Are physically slightly longer, making getting the O2 sensor wrench on them more of a pain. The two sensors should be identical except that the tertiary one has a noticeably longer pigtail on it.

2. O2 wrench - DO go to AutoZone and rent this bad boy. Are you ever going to do this again? Hopefully not anytime soon. No real reason to buy one of your own for this unless you just really want one.

3. WD-40.

4. 2x flathead Screwdrivers

PROCEDURE:
1. Pull the car up on ramps and chock the rear wheels. Unless you have a lift in which case I'm incredibly jealous and why are you reading this basic of a DIY anyway?
2. Remove the plastic undercarriage shield. Use your two flathead screwdrivers to pop up the center of each plastic pop-rivet, then just pull them out.

These things are evil, and you'll find if you take this shield off often that they break easily. You can live with a couple missing, but too many and you'll find yourself scraping trash off the interstate. DoT might appreciate it, but you certainly won't. I ordered a bag of them off Amazon, look for "bumper clips" and make sure they are the same size (head diameter, stem length, hole size). It otherwise doesn't matter whether they are labeled for a Honda or an Acura, etc.

3. Disconnect the sensor pigtails. The side of the connector has little plastic tabs that you'll need to squeeze. I personally found it easiest to use one hand to pinch tabs and a flathead screwdriver to wedge the connectors apart. Be careful not to damage the connector.

4. Liberally apply WD-40 to the bottom of the sensors, where they screw into the cat. Make your life easy. I let it set for a while, then reapplied right before I went to loosen them and even with my complete and utter lack of upper body strength I was able to get them off.

5.Put the special wrench you borrowed onto the bottom of the O2 sensor and unscrew it.

6. Take the replacement O2 sensor with the shorter pigtail out of the bag and screw it in where the old secondary one was. Tighten with wrench but do not overtighten. Repeat for tertiary sensor (with the longer pigtail).

7. Plug the connectors back in. They should snap in place.

8. Replace the undercarriage shield and you're done! You may need to drive it for a day or so before the MIL clears.

That's it, that's all there is to it. Now you can tell your non-car friends "yeah, I replaced the secondary and tertiary O2 sensors" and they'll think you've done something impressive!

nana_ily1990

so i need to get 2 o2 sensor?
what happens if i only change one

Leliel

What trouble code is the OBDII throwing?

If you need to change the PRIMARY O2 sensor (likely "bank1, sensor 1"), then no, just change the 1.

If you have a hybrid like mine and need to change the SECONDARY OR TERTIARY O2 sensor, then yes change them both at the same time. I found the codes my car was throwing weren't terribly clear on which one it thought was the problem, so you could easily replace the wrong one. And since they are in series, it seems not terribly unlikely they could go at near the same time anyway.

If you have a regular 4-cyl Civic , then you probably only have 1 cataclytic converter, so don't have a tertiary sensor and can just change whichever of the primary or secondary is throwing the code.