Denso o2 Sensor

[Nelsonmd]

Update...

Ok, so I installed the new O2 sensor into my pastor's 96 ltd last night and all went very smoothly. I got under the vehicle and found 1 reason for the problems, the nuts were completely rusted away...

I was able to pull the old sensor right off. I cleaned the threads with a die, scraped the rusted on old gasket off, and put the new sensor on with some new flange bolts. They will rust away as they aren't stainless (I don't think), but oh well, they were cheap and available.

Here is the before and after for tail length comparison...

The new tail is definitely longer than the old one by maybe an inch or so, and it fit in just fine (I should have taken a side-by-side, but forgot to). I had a tough time unplugging the old sensor as it had been splattered with grease and grit from the DS, which clogged the connector release tab.

I need to get back under my rig and take a picture of the O2 sensor vehicle side harness, because I suspect my vehicle side harness is shorter than his. I'll post that when I get it. If it is longer, then my next O2 sensor is going to be a 234-4153. I will also send the pictures to Denso so maybe they can correct their website.

 

[4ganger]

So what are the correct part numebrs for a 2000 SR5 Sport

Front of the cat 234-4162 (10.63in)
After the Cat 234-4154 (12.91in)

BTW advance auto parts DEALIO does work. It gets $20 off not 20%. Cost is still $89.99 ea. Ouch.

Bigger question is do we really need to replace the one after the cat? Seems to me the one before the cat would tell the engine something and need to be replaced (i.e. engine adjusting A/F mix) while the one after the cat is just to ensure it is meeting emissions and so who cares unless it is throwing a code. Anyone know?

 

[Nelsonmd]

So what are the correct part numebrs for a 2000 SR5 Sport

Front of the cat 234-4162 (10.63in)
After the Cat 234-4154 (12.91in)

BTW advance auto parts DEALIO does work. It gets $20 off not 20%. Cost is still $89.99 ea. Ouch.

Bigger question is do we really need to replace the one after the cat? Seems to me the one before the cat would tell the engine something and need to be replaced (i.e. engine adjusting A/F mix) while the one after the cat is just to ensure it is meeting emissions and so who cares unless it is throwing a code. Anyone know?

Even with the discount, it is cheaper to get it off amazon...

The after cat sensor does only throw codes, but it seems to go out more frequently, and you can't pass inspection with a CEL, hence, we have to replace them.

As far as the right one for the 2000 SR5 sport, it's wet out and I am in work clothes, so I can't get a pic now to check the length of my vehicle harness, but I will get one later. If I were ordering one today, I would order the 234-4153.

 

[Nelsonmd]

Holy cow, I'm a dumbass...

I figured out why mine didn't fit. I have Cali emissions:ybrick:. I had checked for the emissions sticker under the hood, and my sticker doesn't say that it is Cali, and somehow i never actually counted the number of cats I have.

For all the hours I have spent on my back underneath this thing, how the f did I not notice I have 2 CATs?

Well there you go, I should have ordered 234-4153 in the first place.

Here are some pics to show my dumbass-ery...

Well, one thing's for sure, I am never fixing my P0420 code, the price for fixing it just doubled...

In conclusion, F%$# California.

 

[ksroqclimber]

Added to Tutorial & Documentation Reference.

 

[Nelsonmd]

Added to Tutorial & Documentation Reference.

Aww, my dumb-assery just got stickied...

 

[rpearlberg]

I'm going to attempt to replace these myself....
what size/model number do I get for a 2001 4Runner SR5?

I plan to order Denso from Amazon.

Thanks!!

 

[rpearlberg]

This is from Denso's website:

Oxygen Sensors
234-4261
Downstream, OE Style ($66.80 on Amazon)

234-4209
Downstream, Universal ($37.90 on Amazon)

Air Fuel Ratio Sensor
234-9002
Upstream, OE Style


What do I need to get????

 

[Nelsonmd]

This is from Denso's website:

Oxygen Sensors
234-4261
Downstream, OE Style ($66.80 on Amazon)

234-4209
Downstream, Universal ($37.90 on Amazon)

Air Fuel Ratio Sensor
234-9002
Upstream, OE Style


What do I need to get????

Glad you found your way over here. Follow the link to the URD website posted here earlier. It will tell you exactly what you need.

 

[rpearlberg]

Thanks!

So looks like I need:

234-4261
234-9002

Comes to $161.65 on Amazon.

Does that sound about right? Hopefully I can do this myself, if not how much should I expect to pay for someone to do it for me?

 

[Nelsonmd]

Thanks!

So looks like I need:

234-4261
234-9002

Comes to $161.65 on Amazon.

Does that sound about right? Hopefully I can do this myself, if not how much should I expect to pay for someone to do it for me?

Sounds about right.

Read up on it here, and you should be able to do it yourself. Excessive rust will make it harder, but it's totally doable.

 

[TegoXR]

Alright so whats the verdict for the Air/Fuel Sensor before the cat for NON CALI TRUCKS?

234-4162

 

[TheDurk]

Alright so whats the verdict for the Air/Fuel Sensor before the cat for NON CALI TRUCKS?

234-4162

Trick question, huh?? (There are no air/fuel sensors on non-Cali. trucks, unless you mean 2001-2002 when the two-cat system was on all trucks.)

The 234-4162 is an O2 sensor, not an A/F sensor, good for the upstream sensor on 4WD or 2WD auto trans (all engines) from '96 to 2000 excluding Cali. 's. . Not good for manual trans.

Note: If you are getting a code that says Air/fuel sensor on your 1999, odds are that you indeed have a Cali. truck so be very sure before you spend your money. In '99 and 2000, Cali. trucks were sold all over the country--including my '99 here in NJ. Several other states opted into the Cali. standards in 1999 and 2000. Get under the truck and count cats.

 

[KHoffRunner]

My truck throws a cel about once every two weeks and its completely random. Its never lasted more than 24 hours and some one said it was prolly my o2, but the truck is running really good right now. Also it shows no codes

 

[TegoXR]

So what sensor would I need for a '99 4Runner 2WD V6 Auto with ONE CAT?

 

[RdRunNNeR]

Trying to revive this thread. Got a P0420 code and need to replace my rear O2 sensor. I have a 99 Cali Emissions 2 Cat set-up.

I believe this is the correct part # for the front A/F ratio sensor: 234-9002
but what is the correct part # of the rear sensor??? :clock:

 

[TheDurk]

Trying to revive this thread. Got a P0420 code and need to replace my rear O2 sensor. I have a 99 Cali Emissions 2 Cat set-up.

I believe this is the correct part # for the front A/F ratio sensor: 234-9002
but what is the correct part # of the rear sensor??? :clock:

4x4/RWD; Auto/Manual; 3.4l V6/2.7l I4?

 

[Nelsonmd]

Trying to revive this thread. Got a P0420 code and need to replace my rear O2 sensor. I have a 99 Cali Emissions 2 Cat set-up.

I believe this is the correct part # for the front A/F ratio sensor: 234-9002
but what is the correct part # of the rear sensor??? :clock:

Go back to the second post of this thread, the URD chart is correct. Look up your specs there.

 

[RdRunNNeR]

3.4L auto 4x4. Sorry fellas found it on the URD spec chart, appreciate the help. Hopefully this will solve my problem. If the thread posts that the nuts of the sensor bolt onto brake or are left with no thread am I screwed? Is there a workaround if this happens? It's fairly rusted out, I'll pb blaster the hell outta it but im just curious.

 

[TheDurk]

3.4L auto 4x4. Sorry fellas found it on the URD spec chart, appreciate the help. Hopefully this will solve my problem. If the thread posts that the nuts of the sensor bolt onto brake or are left with no thread am I screwed? Is there a workaround if this happens? It's fairly rusted out, I'll pb blaster the hell outta it but im just curious.

Usually only a minor pain. The studs are a pantload harder than the nuts, which you can break off if you have to, then clean up the studs with a wire brush. You might as well get new nuts up front if you are rusted: 90179-08059 at the stealer or any stainless M8-1.25 nut you can find.