Code 21

[gp-7mgte]

Checked my codes today because my car is hesitating bucking, and i got a code 21 which is the O2. But i just recently changed my O2 with a brand new one from toyota. so i was wondering if anything else would cause the car to throw that code. would faulty catalytic converter make this happen. because i removed the cat underneath the car with a test pipe, and still have stock down pipe on, but when i hit fuel cut the car backfires and fire actually comes out. i thought u couldnt backfire with a cat still on unless it was shot? so just wondering if anything else would cause code 21 to come out?

 

[Godspeed]

21 is also oxygen sensor heater signal on 90 and later turbo models

 

[gp-7mgte]

21 is also oxygen sensor heater signal on 90 and later turbo models

i am an early 89, so i guess that doesnt apply to me.

 

[jetjock]

Clear the code and try again. Code 21 will not cause your car to "buck" so the code is from the buck and not the other way around. Me thinks.you've got more problems than a bad sensor as the car will not run noticeably different with a bad one than one that's working. That it will is a common misconception. In fact it'll run slightly better. The cat won't cause this code either.You can check the sensor by measuring Vf to ground with the diag block shorted. Do you also have code 22? A bad water temp sensor can also cause a bad O2 signal. Got a code 25 or 26?

 

[gp-7mgte]

Clear the code and try again. Code 21 will not cause your car to "buck" so the code is from the buck and not the other way around. Me thinks.you've got more problems than a bad sensor as the car will not run noticeably different with a bad one than one that's working. That it will is a common misconception. In fact it'll run slightly better. The cat won't cause this code either.You can check the sensor by measuring Vf to ground with the diag block shorted. Do you also have code 22? A bad water temp sensor can also cause a bad O2 signal. Got a code 25 or 26?

i have a 41 tps code aswell, but i just wanted to see if the 21 had anything to do with my hesitation, because i just but that new O2.

 

[jetjock]

A bad TPS will certainly cause the engine to act weird. Since that is obvious and since you exepcted help while witholding information (thereby forcing me to waste time playing 20 questions) you're now on my list. Guards, take him away....