Oxygen Sensor Help

suprajim · 10-14-2009, 03:16 AM

Hello everyone. I am new to the forums and needed some help. I have searched and couldn't locate any other posts that answered my question. The Check Engine light on my 92 Turbo is on and I did the diagnostic check and got Code 21. So I replaced the oxygen sensor with a new 3 wire Denso. I pulled the EFI fuse and also unhooked the battery when changing it out. The plug was broken, so instead of going to the junk yard or dealership to find another one, I just cut the plug off and used butt connectors and crimped the wires together. I hooked everything back up and the light is still on and I still get Code 21. The wires at the sensor seem ok, but not really sure if it could be a problem on the other end. I'm not really sure where the other end of the wires actually leads to. Is there something else I should check? Should I trace the wires back and just try to completely replace the wiring? Any help would be appreciated.

2jzmaestro · 10-14-2009, 06:05 PM

replacing all the wiring will gurantee any malfunctioning problems. Especially because you have altered the wiring your self, diagnostics of your car isnt as accurate.

If you are looking for OEM parts for cheap, i suggest this site http://toyotapartszone.com

they have pretty cheap parts

hope this helps

Krem · 10-15-2009, 08:26 PM

You'll attract more flies with honey than you will shit... if advice is not usefull, please try to keep it to yourself... otherwise no one will feel like helping you. I've already noticed this community seems to ignore threads w/o comments in reply to the OP... I'm pretty sure you don't want them to ignore posts created by your user name.

Having given my etiquette bit... I'd suggest getting your hands on an Ohm meter and ensuring you're getting the right input and receiving the right output values. Code 21 could be o2 sensor, o2 sensor heater, or your ECU... checking the rate of ohm's thru the parts might help determine where the problem is.. I hope it's not your ECU... that's a big fear of mine regarding my mk3, and I wouldn't wish that upon anyone... good luck, and update this thread based on your findings.. people can generally give better help/advice when there is more details that are included... also, the more specific the detail, the better...

suprajim · 10-15-2009, 08:38 PM

Thanks, Krem. I looked in the TSRM and followed the instructions checking the code with an ohm meter. It pointed to the O2 sensor being bad, that is when I replaced it. However, I haven't tried it again since it was replaced. I personally don't know how to read an ohm meter, but my friend assured me we initially did it right. I will have to get with him and see if we can check it again and come up with the same results. Maybe I should really learn how to use one since I am probably going to need it in the future with this car. I sure hope it's not an ECU issue. Thanks again for the advice.

Krem · 10-15-2009, 10:21 PM

Hmmm, well, hopefully you find the issue... at least after switching the sensor, if you get the same readings on the ohm meter, you can be sure the problem exists either in the user (kidding

) or the power being supplied to the sensor itself. As long as it's not the ECU, hopefully you'll be in the clear. Hope you get it fixed, I was without my mk3 for about 3 weeks, and I don't wish that deprevation upon anyone... I swear I was going thru withdrawls even tho I only had been driving it two weeks before it died... towards the end, I was out there pretending to shift gears as I made the engine noises myself... beatbox style...

10-14-2009, 03:16 AM	#1
suprajim Intake Join Date: Jul 2009 Location: Dallas, TX Posts: 36	Oxygen Sensor Help Hello everyone. I am new to the forums and needed some help. I have searched and couldn't locate any other posts that answered my question. The Check Engine light on my 92 Turbo is on and I did the diagnostic check and got Code 21. So I replaced the oxygen sensor with a new 3 wire Denso. I pulled the EFI fuse and also unhooked the battery when changing it out. The plug was broken, so instead of going to the junk yard or dealership to find another one, I just cut the plug off and used butt connectors and crimped the wires together. I hooked everything back up and the light is still on and I still get Code 21. The wires at the sensor seem ok, but not really sure if it could be a problem on the other end. I'm not really sure where the other end of the wires actually leads to. Is there something else I should check? Should I trace the wires back and just try to completely replace the wiring? Any help would be appreciated. Last edited by suprajim; 10-14-2009 at 04:03 AM. Reason: Correction. I replaced with new Denso O2 sensor

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10-14-2009, 06:05 PM	#2
2jzmaestro Stock Join Date: Sep 2009 Location: LOS ANGELES Posts: 25	replacing all the wiring will gurantee any malfunctioning problems. Especially because you have altered the wiring your self, diagnostics of your car isnt as accurate. If you are looking for OEM parts for cheap, i suggest this site http://toyotapartszone.com they have pretty cheap parts hope this helps

10-15-2009, 08:26 PM	#3
Krem 3" Exhaust Join Date: Sep 2009 Location: Las Vegas Posts: 167	You'll attract more flies with honey than you will shit... if advice is not usefull, please try to keep it to yourself... otherwise no one will feel like helping you. I've already noticed this community seems to ignore threads w/o comments in reply to the OP... I'm pretty sure you don't want them to ignore posts created by your user name. Having given my etiquette bit... I'd suggest getting your hands on an Ohm meter and ensuring you're getting the right input and receiving the right output values. Code 21 could be o2 sensor, o2 sensor heater, or your ECU... checking the rate of ohm's thru the parts might help determine where the problem is.. I hope it's not your ECU... that's a big fear of mine regarding my mk3, and I wouldn't wish that upon anyone... good luck, and update this thread based on your findings.. people can generally give better help/advice when there is more details that are included... also, the more specific the detail, the better...

10-15-2009, 08:38 PM	#4
suprajim Intake Join Date: Jul 2009 Location: Dallas, TX Posts: 36	Thanks, Krem. I looked in the TSRM and followed the instructions checking the code with an ohm meter. It pointed to the O2 sensor being bad, that is when I replaced it. However, I haven't tried it again since it was replaced. I personally don't know how to read an ohm meter, but my friend assured me we initially did it right. I will have to get with him and see if we can check it again and come up with the same results. Maybe I should really learn how to use one since I am probably going to need it in the future with this car. I sure hope it's not an ECU issue. Thanks again for the advice.

10-15-2009, 10:21 PM	#5
Krem 3" Exhaust Join Date: Sep 2009 Location: Las Vegas Posts: 167	Hmmm, well, hopefully you find the issue... at least after switching the sensor, if you get the same readings on the ohm meter, you can be sure the problem exists either in the user (kidding ) or the power being supplied to the sensor itself. As long as it's not the ECU, hopefully you'll be in the clear. Hope you get it fixed, I was without my mk3 for about 3 weeks, and I don't wish that deprevation upon anyone... I swear I was going thru withdrawls even tho I only had been driving it two weeks before it died... towards the end, I was out there pretending to shift gears as I made the engine noises myself... beatbox style...