Bad 02 sensor - Cars & Trucks

that is not the OEM makers statement on P0401.
truth is this. V6 engine? 3.3L and 3.5L???????
o2 sensor circuit no activity detected bank 1 sensor 2)
means the right rear 02 sensor reads dead.

right bank down stream 02 is dead.

and has zero to to with rich or lean, it is the rear sensor 2.
the rear sensors are only to this bank1 CAT for good quality.
not told at all , what engine is there. v6 sure,3.3 or 3.5L
nor how the engine runs and car drives. ?
or if this is ONLY a smog question and check engine lamp glows?
causes of 401 are
wires to right rear 02 cut burned or damaged , loose or fell off 02.
bad o2 B1,S2 rear of cat bad
bad CAT bank1,
exhaust cracks in CAT sucking air and making any 02 sensor to read dead, near it.
this post ASSUMES , no other DTC errors stored or live running,
assumes scanned LTFT PID reads correctly and no B1S1 02 errors.(front sensor)
bank 1 or B1 is right front engine bank. (drivers view)
facing engine is left bank. (workers viewed)
ASSSMEs car is driven plenty not just parked in an old barn.
A DRIVEN CAR !

SMog tests fail too for monitor cat bank1 dead.
or incomplete status on bank1 cat.

all electrics in car have fuses, (or CB)
all.
cept starter, take 1000 amp fuse there $$$ so its not there.
why not just test all fuses?
i use a volt meter, key on, 12vdc both sides.
or measure each with ohm meter (res) 0 ohms is good.

scan tools
first clear all codes, then drive.
do not drive them off , unless gas and time are cheap..
push the reset button. on the tool.
do not post phone numbers unless identity thief and phone spam are fun... wild idea that.... why do that?

the car has more than 1 oxy sensor,
P0137 is the rear 02 senson not front
and is stuck low,
stuck low is cause by 3 things, (more)
1: BAD SENSOR. or heater bad.
2: 0V ON SENSOR CAN BE EXHAUST LEAKS near it. if heater is good.
3: wires bad to it."connections"
0037 means bad heater on same 02. (Fix this first)
If that is bad, then the 137s are normal (cause and effect normal ,normal for a dead heater.)
the heater must get hot or the 02 is just a brick, useless. (the ecu measures the heater currents)

my guess, dont know the reset button? on scan tool?
guess 2, wrong 02 changed out.
or the wire to it are bad.

now to answer the fuse question , dead accurate ! from FSM.
this car the ECU powers up the 02 heater directly (2 wires)
and measures the heater current doing so, so it can tell you
the heater is dead, it is.! (if after reset and driving it comes back)
the ECU fuses are the fuses that run the heaters
but if those are blown the ECU GOES DEAD.
so, it's not fuses. nice guess, and is first in most cases, but not this time.

some cars in other countries are not wired like our USA cars, and do have relays and fuses here.
but only 4 people in 1 GAH-gillion posts ever told where they live, (hi, my car is UK car)
can i assume the 603 prefix is here.
some folk can buy any cell numbers, so is not telling me much.

did you replace to top intake gasket you removed when you replaced the back spark plugs ,and do you torque it down right

If it's still reading 02 sensors and you replaced them AND assuming you cleared codes I suspect bad cat, converters, The 02 sensors when everything is operating properly, the front 02 sensors read different from rear ones - if they read the same, you get code/light. Plus with your description sounds like bad converter(s)

Are you sure it's 02 sensors? Just because code says 02 sensors doesn't necessarily mean they're bad. Bad 02 sensor code can also indicate bad cat. converter. If 02 sensors read exact same reading before and after converter they will trigger OBC to "sensor fault" - they should be reading 2 different readings. (Pre CAT/POST cat) I'd suggest replacing cat converter before replacing sensors.

It's an 02 sensor (oxygen sensor) fault. One if your 02 sensors is bad and/or catalytic converter is bad.

bank 1 sensors you have 2 on exhaust bank 2 you have 2 sensors there are 4 02 sensors they range in cost of $75.00 each it will be much easier to replace one at a time. reset your computer each time by disconnecting the positive cable from your battery for 10 mins. each time. you can do this several times, or you can take it to mechanic that has code reader to tell you which is bad. $75.00 minumal cost. you can reset the computer in the truck by disconnecting the positive cable from the battery for 5 to 10 minutes,10 recommened. this will make the light go of, but if you have a bad 02 sensor it will come back on.your 02 sensors are in the exhaust system just behind the motor. hard to get to,need special tool to remove them,but you can purchase at autozone,or advance auto for $20.00 for the tool. the 02 sensors range in price $75.00 each to $85.00 and can go higher. you need to be sure which is bad. or be prepared to pay.hope this helps and thank you for choosingfixya.com. we are here 24/7 to assist thank you!

check engine light on when tested it says bad o2 sensor did you replace 02 sensor it takes driveing it so many miles before light will go off give it couple days you dont need cadillac converter check engine light will go off cv joint they click as you turn dont let a mechanic sell you something you dont need its very rare for cadillac converters to go bad its common for o2 sensors to go bad like yours did but when 02 sensors are replaced it takes driveing it for awhile before it resets itself you also have more then one 02 sensor was then wrong one replaced they screw into your exaust manifold

assueming it has the v-6 in it look at the exhaust pipe comming off the side of the engine there will be two up stream 02 sensors which are heated and one downstream past catalitic conveter. If may have the second style with the Y cross over with 1 upstream before the cat and one after. The difference between the 0-2 sensors is the upstrean are heated so it goes into closed loop faster. I find that on most of these the up stream 02 sensor heaters have failed. You can go to a Autozone and they can pull the codes for you and tell you which side it is that needs to be replaced. However 02 sensors get old after time and they start shifting slowly, if it shifts slowly then it's called a lazy 02 sensor. And will send a code to the computer, if you get the trouble code of the 02 sensor heater is bad you will have to change it, I recommend Replacing both. The reason is if one is going bad the other will soon follow. You can buy a socket wrench For the 02 sensors for 12 dollars makes it real easy to replace the 02 sensors when they are COLD. Hope this helps and thanks for using fix-ya.

if the 02 sensor is unplugged and you are reading a scan tool from the diagnostic link then of course the 02 reading is wrong
if you are using a volt meter right at the connector thats on the sensor then the 02 will read lean because the heating elements in it are disconnected when you unplug it
check 02 voltage with engine warmed up and 02 sensor connected you will have to pierce insulation with your probe