What would happen if O2 sensors were switched by accident?

YM13 · 02-01-2012, 05:34 PM

In reference to the title, I ask this question because about a year ago my check engine light came on and the dealership told me my 02 sensor needed to be replaced. So about a year afterwards I bought both, and had a shop deal with the rusted bolts and put them in. However, I have not noticed a real change in gas mileage since then and I have replaced spark plugs, cleaned MAF and cleaned the air filter (K&N). Gas mileage is not only undesirable but it is a lot less than what it used to be. So I am wondering what if the garage swapped the two sensors? Would this throw a code or would the vehicle keep going with some sort of false readings contributing to poor gas mileage. If so, how do I find out or check? is there a number on the actual 02 sensors themselves?

Thanks in advance!

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YM13 · 02-02-2012, 12:57 PM

Anyone have any thoughts?

TheDurk · 02-02-2012, 02:23 PM

As long as the plugs fit and the wires reach, on a '97 it would make NO difference whatsoever. Look here: http://www.densoaftermarket.com/cata....php?part=o2sn

The same universal is used front and back 234-4206 on all models. The only differences among the application specific sensors are wire length and possibly plug configuration--but I suspect the plugs are indeed the same.

Whole different deal on a '01-'02 or a '99-'00 Cali. The front and rear sensors are TOTALLY different. Aside from the plugs not fitting, I'm sure the ECM would freak out. Not to mention the '01 and '02 have one screw-in and one flange type.

YM13 · 02-02-2012, 05:05 PM

I ordered the 4161 and the 4154 from amazon...with those two different O2 sensors will there be any difference?

**waskillywabbit** · 02-02-2012, 05:18 PM

If something was wrong with your O2 sensor(s) your CEL would have told you right away.

YM13 · 02-02-2012, 06:08 PM

Alrighty thanks for the help...I guess I'll have to scour the "why is my gas mileage bad" posts to find some answers on what may be happening...

yotaman85 · 02-02-2012, 06:13 PM

what is you MPG?

TheDurk · 02-02-2012, 06:22 PM

Quote:

Originally Posted by YM13

I ordered the 4161 and the 4154 from amazon...with those two different O2 sensors will there be any difference?

4161 is 15.35 in long. 4154 is 12.91 in long. The plug looks to be perfectly identical. The sensor itself IS identical. The only difference is wire length. If you try and put the 4154 in the upstream hole, the wire might not reach, but if it does, it will work exactly the same as the 4161. On the downstream hole, the 4161 will have too long a wire, but will function perfectly.

YM13 · 02-02-2012, 06:43 PM

Quote:

Originally Posted by TheDurk

4161 is 15.35 in long. 4154 is 12.91 in long. The plug looks to be perfectly identical. The sensor itself IS identical. The only difference is wire length. If you try and put the 4154 in the upstream hole, the wire might not reach, but if it does, it will work exactly the same as the 4161. On the downstream hole, the 4161 will have too long a wire, but will function perfectly.

Awesome thanks for that information!

YM13 · 02-02-2012, 06:46 PM

Quote:

Originally Posted by yotaman85

what is you MPG?

I get around 13 maybe 14 around the city and that is babying the pedal cruising around..I used to get 17 or so...

02-02-2012, 12:57 PM	#2 (permalink)
YM13 Registered User Personal Sales Rating: (0) [OP] Join Date: Oct 2006 Location: Columbia, SC Posts: 422	Anyone have any thoughts? __________________ \| '97 4runner 5spd SR5 w/ Tan leather int. \| Diff. Breather \| Hella 500 Driving Lights \| Alpine 9856 Headunit \| Old Man Emu 3" lift from Toytec \| Green Tokicko Shocks\| 265/75/16 BFG A/T \| SS Diff. Drop \| Polk Audio db6501 components \| Profile AP600 amp. \| Alpine MRP-M1005 amp \| 1 Polk Audio SR124 DVC Subwoofer \|

02-02-2012, 02:23 PM	#3 (permalink)
TheDurk Registered User Personal Sales Rating: (0) Join Date: Feb 2007 Location: New Jersey and Sao Paulo Posts: 535	As long as the plugs fit and the wires reach, on a '97 it would make NO difference whatsoever. Look here: http://www.densoaftermarket.com/cata....php?part=o2sn The same universal is used front and back 234-4206 on all models. The only differences among the application specific sensors are wire length and possibly plug configuration--but I suspect the plugs are indeed the same. Whole different deal on a '01-'02 or a '99-'00 Cali. The front and rear sensors are TOTALLY different. Aside from the plugs not fitting, I'm sure the ECM would freak out. Not to mention the '01 and '02 have one screw-in and one flange type. __________________ '99 "tall" 4Runner SR5 5sp 4WD 3.4 V6(U.S)--no boards, Hella Fogs, Trekmaster shocks, FIAMM horns, Alpine sound, stock otherwise, owned since new. '97 HiLux SW4 (Japan model assembled in Argentina, bought in Brazil, very close to a 3.0 4Runner/Surf) '71 FordWillys Jeep CJ5 (with straight six Ford Maverick 3.0 liter engine--lives in the mountains north of Sao Paulo Brazil) Last edited by TheDurk; 02-02-2012 at 02:31 PM.

02-02-2012, 05:05 PM	#4 (permalink)
YM13 Registered User Personal Sales Rating: (0) [OP] Join Date: Oct 2006 Location: Columbia, SC Posts: 422	I ordered the 4161 and the 4154 from amazon...with those two different O2 sensors will there be any difference? __________________ \| '97 4runner 5spd SR5 w/ Tan leather int. \| Diff. Breather \| Hella 500 Driving Lights \| Alpine 9856 Headunit \| Old Man Emu 3" lift from Toytec \| Green Tokicko Shocks\| 265/75/16 BFG A/T \| SS Diff. Drop \| Polk Audio db6501 components \| Profile AP600 amp. \| Alpine MRP-M1005 amp \| 1 Polk Audio SR124 DVC Subwoofer \|

02-02-2012, 05:18 PM	#5 (permalink)
waskillywabbit Certified Goat Herder Personal Sales Rating: (10) Staff Join Date: Jul 2003 Location: Tuscaloosa, AL Posts: 24,696	If something was wrong with your O2 sensor(s) your CEL would have told you right away. __________________ WabFab Off-Road, LLC 10% OFF FOR YOTATECH MEMBERS AISIN Manual Hubs \| Bikini Top Kits \| Endlinks or Discos \| Slider Adapters & Wabbit's Foot \| Tshirts & Stickers \| Wheel Spacers

02-02-2012, 06:08 PM	#6 (permalink)
YM13 Registered User Personal Sales Rating: (0) [OP] Join Date: Oct 2006 Location: Columbia, SC Posts: 422	Alrighty thanks for the help...I guess I'll have to scour the "why is my gas mileage bad" posts to find some answers on what may be happening... __________________ \| '97 4runner 5spd SR5 w/ Tan leather int. \| Diff. Breather \| Hella 500 Driving Lights \| Alpine 9856 Headunit \| Old Man Emu 3" lift from Toytec \| Green Tokicko Shocks\| 265/75/16 BFG A/T \| SS Diff. Drop \| Polk Audio db6501 components \| Profile AP600 amp. \| Alpine MRP-M1005 amp \| 1 Polk Audio SR124 DVC Subwoofer \|

02-02-2012, 06:13 PM	#7 (permalink)
yotaman85 Registered User Personal Sales Rating: (0) Join Date: Feb 2008 Location: hendersonville, TN. Posts: 1,390	what is you MPG? __________________ IF ANYBODY EVER GIVES YOU CRAP FOR NOT HAVING ENOUGH MODS REMIND THEM "I DONT NEED MODS, I WHEEL A TOYOTA!" if you havn't heard yet, if it kills babies i dont like it. '86 P/U 22Re, 5 speed, 4x4, 33" A/T's, 63" chevies. beat to death and SOLD '88 P/U 22Re, 5 speed, 4x4, 33" M/T's, lincoln locker, custom leafs, open IFS, cranked torsion bars. ROLLED AND SOLD. '90 4runner, SR5 3.0, auto. 4x4, 30" A/T, stock! SOLD I NEED ANOTHER TOYOTA ASAP...

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02-02-2012, 06:46 PM
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