Code 21
 

hey guys.. my engine light came on again.. last time the battery ran out and it didn't come back on after the jump.. but now it's back.. i put a wire on the TE1 and E1 and put the key to ON. but not start the engine... anyways.. 21 means Main O2S & Heater Signal .. anyone know what that's suppost to mean?? or better yet.. what i need to replaces or can i repair it(i'm poor not cheap)?? and how much??.. thanks guys.

oxygen sensor

so if i replaces the O2 senser. it'll fix code 21 .... can someone tell me how it works?
cuz the 93 engine has two O2 senser.. if i replaces one.. how do i know if it's the correct one?/ would the check engine light just disapare??..

Unplug the wire, take off the bolt, and nut holding the front o2 sensor on.
Instillation is the opposite of taking it out. Pull the EFI fuse out of the fuse box, and put it back in. The code will reset faster than you cant ake it out and put it in.

just wondering..
 

if ONLY the O2 sensor need to be replaces.. shouldn't it give me code 28(main O2S)??.. but it gave me 21. main O2S and Heater SIgnal.... what is the Heater Signal???.. sorry i'm being a pain in the ass.. haha. just craving for more learning.

Moving this to Maintenance ;)

C'on guys
 

there's gotta be somebody out there that knows excatly what code 21 is on a 93 ES300..
i was told there's 3 O2 Sensor in the car.. code 28 means O2Sensor and 21 means O2Sensor and Heater Singal.. then there musta be one Sensor out of the three that's a little different.. can anyone tell me??

and if i'm to replaces it.. what O2 Sensor right for it??..

ok i have done a little research

code 21 is the Oxygen sensor

code 28 is the No. 2 Oxygen Sensor signal

now ive read there a 3 sensors ....Two are located on the headers.....one for each bank. The other is after the cat.

as far as the heater signal goes can you tell me where you got that info

the first sensor is right on the exhaust manifold

replace this one first since thats is the code you are getting

let me know if this works

thanks man.. i'll get the cheapest O2 sensor from pepboys and see how it works..

as for the info on the codes.. i got it from troublecodes.net

so does replacing your Oxygen sensor works?

Code 21?
 

:sad: I just went to check my car and I got a "Code 21:Oxygen Sensor Signal or Circuit fault". Which Oxygen sensor is it on my 2000 RX300 with 1MZ-FE (3.0 c.c V-6) engine?

sorry to keep you waitting.. i haven't replace it yet.. i got the dam sensor.. but my Y pipe(front pipe) also broke and need to be replaces.. since it can't be seal up( or can it?? ) i'm going to change this y pipe and put on the O2 sensor at teh same time. cuz i think the sensor's on the pipe... so two bird with one stone. ya know. =). i'll let ya know how it turn out..

i also have a code 21 coming up on my RX300. and i got the same engine as yours 1MZ-FE.
and i dont know which one is causing the problem? is it the one that is attached on the exhaust headers? how many oxygen sensors are there anyway? is it also called an air/fuel ratio sensor?

sorry bro. my engine is a 3VZ-FE... 1MZFE are the 94 - 96.. but if the codes are the same.(i'm really NOT 100% sure).. you're have to change the block 1 sensor but if you're changing that, mind as well change the one on the front also.. cuz block 1 is the pain in the ass... there's a total of 3 sensor in your car and 2 is before the cat which is also refer to as the Main sensors, and the one is after the cat is call the Sub sensor... and code 21 means before the cat.. you can get these sensor for around 30 - 40 bucks each(in www.rockauto.com ) . i got a universal Denso.. but i guess you can choose whatever brand like walker or bosch. whichever is light on the wallet.. ..

air/fuel ratio sensor.. umm. i'm pretty sure that can also be another name for the O2 sensor. cuz that's what it does.. it feeds back to your computer on how much air or fuel is needed to have a good mixture... so with a bad sesnor. your computer might go on default and did you feel any lost in power or bad MPG??

thanks for the info. i was checking the part no. on my existing oxygen sensor and found out the number is the old 89467-48010 suspectable one. i saw this on the lexus technical bulletin https://www.clublexus.com/index.php/...ew/1944/1/436/ so i guess this must be the root of my problem. And i have to change 2, each on the exhaust headers.

just wondering if other make oxygen sensor make will do the job as well?