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bad oxygen sensor, can i ignore it?
02-21-11, 12:43 PM
#1
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bad oxygen sensor, can i ignore it?
engine light popped up, and read:
"Air/Fuel ratio sensor circuit response malfunction (bank 1 sensor 1)"
according to the staff at Autozone, i have 2 front and 1 back sensors on my es300 1998, and the one in front is malfunctioning. But he insisted that the O2 sensors are changed in pairs (both front). The parts are not that cheap and come in Exact fit ($110 ea) and Universal Fit ($69).
Should i change only the malfunctioning sensor, or both front ones?
if i ignore the problem, what can it lead to?
can there be any other problem, other than the o2 sensor?
would you recomend changing any other parts near or related to the sensor, so i wont have to pay another visit to the mechanic and pay for labor twice?
other than that the car runs great, had a tune-up recently.
thx
"Air/Fuel ratio sensor circuit response malfunction (bank 1 sensor 1)"
according to the staff at Autozone, i have 2 front and 1 back sensors on my es300 1998, and the one in front is malfunctioning. But he insisted that the O2 sensors are changed in pairs (both front). The parts are not that cheap and come in Exact fit ($110 ea) and Universal Fit ($69).
Should i change only the malfunctioning sensor, or both front ones?
if i ignore the problem, what can it lead to?
can there be any other problem, other than the o2 sensor?
would you recomend changing any other parts near or related to the sensor, so i wont have to pay another visit to the mechanic and pay for labor twice?
other than that the car runs great, had a tune-up recently.
thx
Last edited by ayroman; 02-21-11 at 12:47 PM.
02-21-11, 12:53 PM
#2
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what year car, maybe we can help.
I MAY BE WRONG, but i think the only diff in the exact fit and universal fit is the electrical connection. meaning the exact would plug in and you would need to have your connector cut off and crimped to the pigtail on the universal one.
I MAY BE WRONG, but i think the only diff in the exact fit and universal fit is the electrical connection. meaning the exact would plug in and you would need to have your connector cut off and crimped to the pigtail on the universal one.
02-21-11, 01:53 PM
#3
I replaced only the bank one sensor one Air Fuel ratio sensor on my 1999 ES. Runs great after making the change. Get the Denso model replacement. Its about $105 from Amazon. Also get the exact fit sensor. It makes life so much easier.
For me, the initial symptoms were bucking at cruise speed. Eventually the bucking got so bad at all speeds I stopped driving it until I replaced the sensor.
You are going to have to replace it sooner or later. Save yourself the headache and replace it sooner. Here's a link to the thread to my problem https://www.clublexus.com/forums/es3...ed-advice.html
For me, the initial symptoms were bucking at cruise speed. Eventually the bucking got so bad at all speeds I stopped driving it until I replaced the sensor.
You are going to have to replace it sooner or later. Save yourself the headache and replace it sooner. Here's a link to the thread to my problem https://www.clublexus.com/forums/es3...ed-advice.html
02-21-11, 01:55 PM
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Can you ignore it? No, you can't unless you want to kill your cat and fowl your plugs. Dead o2 sensors tend to make the engine run rich.
It depends on the year of ES300. For the old ones that use the unheated sensors, then change both. These kind of sensors have a shorter life and its recommended that they are changed every 60K miles. For the ES300s with the newer planar type o2 sensors just replace the bad ones. I believe that the 1997 and newer use the planar o2 sensors. Someone will have to verify this though.
However, as many have said on the Legend forum, if one sensor is dead, the other is not far behind. It is your choice to replace both. I would recommend changing them yourself to save money. It is easy to do.
Nine3es, you are correct about the different types of sensors.
It depends on the year of ES300. For the old ones that use the unheated sensors, then change both. These kind of sensors have a shorter life and its recommended that they are changed every 60K miles. For the ES300s with the newer planar type o2 sensors just replace the bad ones. I believe that the 1997 and newer use the planar o2 sensors. Someone will have to verify this though.
However, as many have said on the Legend forum, if one sensor is dead, the other is not far behind. It is your choice to replace both. I would recommend changing them yourself to save money. It is easy to do.
Nine3es, you are correct about the different types of sensors.
02-21-11, 02:39 PM
#5
I also used to have a '98 ES. My rear one went at 75K, the front one at 135K. I see no reason to change them both at the same time. But I would not buy the replacement at AutoZone. Toyota OEM parts for me on something this important, thankyouverymuch. 
If you are truly getting an A/F sensor error (not an O2 sensor error) then your car is a CA emissions spec car, as mine was. It does not have O2 sensors, they are Air/Fuel Ratio sensors, slightly different, and more expensive. Tread lightly!
The front one is VERY easy to change, but you do need a special socket to do this. It's a deep socket, with a big slot in it for the wire to feed thru, should only be $10-15 at Sears. I would avoid the temptation to try to use an open-ended wrench on it, if you round off the flats you're going to have a very hard time getting it out. Seriously, it only takes a few minutes and it's easy to reach, right behind the radiator.
Ignoring it will at least ruin your catalytic converter. It may do much worse.
If you are truly getting an A/F sensor error (not an O2 sensor error) then your car is a CA emissions spec car, as mine was. It does not have O2 sensors, they are Air/Fuel Ratio sensors, slightly different, and more expensive. Tread lightly!The front one is VERY easy to change, but you do need a special socket to do this. It's a deep socket, with a big slot in it for the wire to feed thru, should only be $10-15 at Sears. I would avoid the temptation to try to use an open-ended wrench on it, if you round off the flats you're going to have a very hard time getting it out. Seriously, it only takes a few minutes and it's easy to reach, right behind the radiator.
Ignoring it will at least ruin your catalytic converter. It may do much worse.
02-21-11, 03:13 PM
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I also used to have a '98 ES. My rear one went at 75K, the front one at 135K. I see no reason to change them both at the same time. But I would not buy the replacement at AutoZone. Toyota OEM parts for me on something this important, thankyouverymuch. If you are truly getting an A/F sensor error (not an O2 sensor error) then your car is a CA emissions spec car, as mine was. It does not have O2 sensors, they are Air/Fuel Ratio sensors, slightly different, and more expensive. Tread lightly!
The front one is VERY easy to change, but you do need a special socket to do this. It's a deep socket, with a big slot in it for the wire to feed thru, should only be $10-15 at Sears. I would avoid the temptation to try to use an open-ended wrench on it, if you round off the flats you're going to have a very hard time getting it out. Seriously, it only takes a few minutes and it's easy to reach, right behind the radiator.
Ignoring it will at least ruin your catalytic converter. It may do much worse.
If you are truly getting an A/F sensor error (not an O2 sensor error) then your car is a CA emissions spec car, as mine was. It does not have O2 sensors, they are Air/Fuel Ratio sensors, slightly different, and more expensive. Tread lightly!The front one is VERY easy to change, but you do need a special socket to do this. It's a deep socket, with a big slot in it for the wire to feed thru, should only be $10-15 at Sears. I would avoid the temptation to try to use an open-ended wrench on it, if you round off the flats you're going to have a very hard time getting it out. Seriously, it only takes a few minutes and it's easy to reach, right behind the radiator.
Ignoring it will at least ruin your catalytic converter. It may do much worse.
do i need to go under the car? any other tools needed for DIY? i just dont want to start a job and not being able to finish it with the car apart. thx
02-21-11, 03:57 PM
#7
If it is indeed the front bank sensor that has failed, it's very easy to reach from the front of the car. Here's a picture of the engine in my old '98 ES just before I sold it, with the front sensor indicated. It screws into the exhaust manifold, there is a short section of wire on it, then a gray connector.
Besides the special socket I mentioned, you will need a ratchet wrench for the socket (3/8" or 1/2" depending on the socket), and some sort of rust penetrant to help lubricate the threads so it comes out easier ("PB Blaster" is good and easy to find). If the engine is cold, start it up and let it run for only a minute or 2, just to start getting the manifold heated up but not too hot to touch. Shut the engine off, spray the penetrant on the joint where the sensor is, then let it soak for a bit. Disconnect the wire at the connector, then put the socket on the sensor, let the wire drape out thru the slot in the socket. Put the ratchet wrench on the socket, it should take some firm force to get it to break free of the manifold. Once it does, it should spin out easily.
One of the nice things about the new sensor from Toyota is it comes out of the box with anti-sieze already on the threads. You screw it in, snug it tight, and hook up the wires. Close the hood, you should be done, except that you will probably need to get the error code reset on the ECU so the light turns off. Don't be surprised if it pops on again, both of mine did, the engine computer has to get used to the new sensor, so I had to reset it twice (I have a code reader tool). Then it never came back on again.
Besides the special socket I mentioned, you will need a ratchet wrench for the socket (3/8" or 1/2" depending on the socket), and some sort of rust penetrant to help lubricate the threads so it comes out easier ("PB Blaster" is good and easy to find). If the engine is cold, start it up and let it run for only a minute or 2, just to start getting the manifold heated up but not too hot to touch. Shut the engine off, spray the penetrant on the joint where the sensor is, then let it soak for a bit. Disconnect the wire at the connector, then put the socket on the sensor, let the wire drape out thru the slot in the socket. Put the ratchet wrench on the socket, it should take some firm force to get it to break free of the manifold. Once it does, it should spin out easily.
One of the nice things about the new sensor from Toyota is it comes out of the box with anti-sieze already on the threads. You screw it in, snug it tight, and hook up the wires. Close the hood, you should be done, except that you will probably need to get the error code reset on the ECU so the light turns off. Don't be surprised if it pops on again, both of mine did, the engine computer has to get used to the new sensor, so I had to reset it twice (I have a code reader tool). Then it never came back on again.
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02-21-11, 07:37 PM
#8
according to the staff at Autozone, i have 2 front and 1 back sensors on my es300 1999
Engine light popped up, and read:
"Air/Fuel ratio sensor circuit response malfunction (bank 1 sensor 1)"
"Air/Fuel ratio sensor circuit response malfunction (bank 1 sensor 1)"
02-23-11, 01:54 PM
#10
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If it is indeed the front bank sensor that has failed, it's very easy to reach from the front of the car. Here's a picture of the engine in my old '98 ES just before I sold it, with the front sensor indicated. It screws into the exhaust manifold, there is a short section of wire on it, then a gray connector.
Besides the special socket I mentioned, you will need a ratchet wrench for the socket (3/8" or 1/2" depending on the socket), and some sort of rust penetrant to help lubricate the threads so it comes out easier ("PB Blaster" is good and easy to find). If the engine is cold, start it up and let it run for only a minute or 2, just to start getting the manifold heated up but not too hot to touch. Shut the engine off, spray the penetrant on the joint where the sensor is, then let it soak for a bit. Disconnect the wire at the connector, then put the socket on the sensor, let the wire drape out thru the slot in the socket. Put the ratchet wrench on the socket, it should take some firm force to get it to break free of the manifold. Once it does, it should spin out easily.
One of the nice things about the new sensor from Toyota is it comes out of the box with anti-sieze already on the threads. You screw it in, snug it tight, and hook up the wires. Close the hood, you should be done, except that you will probably need to get the error code reset on the ECU so the light turns off. Don't be surprised if it pops on again, both of mine did, the engine computer has to get used to the new sensor, so I had to reset it twice (I have a code reader tool). Then it never came back on again.
Besides the special socket I mentioned, you will need a ratchet wrench for the socket (3/8" or 1/2" depending on the socket), and some sort of rust penetrant to help lubricate the threads so it comes out easier ("PB Blaster" is good and easy to find). If the engine is cold, start it up and let it run for only a minute or 2, just to start getting the manifold heated up but not too hot to touch. Shut the engine off, spray the penetrant on the joint where the sensor is, then let it soak for a bit. Disconnect the wire at the connector, then put the socket on the sensor, let the wire drape out thru the slot in the socket. Put the ratchet wrench on the socket, it should take some firm force to get it to break free of the manifold. Once it does, it should spin out easily.
One of the nice things about the new sensor from Toyota is it comes out of the box with anti-sieze already on the threads. You screw it in, snug it tight, and hook up the wires. Close the hood, you should be done, except that you will probably need to get the error code reset on the ECU so the light turns off. Don't be surprised if it pops on again, both of mine did, the engine computer has to get used to the new sensor, so I had to reset it twice (I have a code reader tool). Then it never came back on again.
02-23-11, 06:08 PM
#13
Bank 1 Sensor 1 is behind the engine, not that front one, not the one farthest back on the exhaust. It's probably the hardest one to change, but nothing too rough.
What is it with B1S1? My CEL just came on recently with an error on B1S1 also. Damn things are around $100 too. :/
I read up on this thread for more info:
http://us.lexusownersclub.com/forums...howtopic=32035
What is it with B1S1? My CEL just came on recently with an error on B1S1 also. Damn things are around $100 too. :/
I read up on this thread for more info:
http://us.lexusownersclub.com/forums...howtopic=32035
02-23-11, 06:56 PM
#14
Can someone please verify if this is in fact the correct sensor for B1S1 on a '95 ES300?
http://www.autozone.com/autozone/par...707572_0_5320_
This is the Universal sensor, but it just appears to not come with the connector. Does my car not have that connector already and I can just use the miniplug it's got wired to it?
Notice:
http://www.autozone.com/autozone/par...5_0_1784_97999
This appears to be an O2 sensor that is applied before the catalytic converter and has that same miniplug, but comes with that connector. I'll buy whatever I need, it would just be cool to save around $50 if I can. ;D (and that said, I can't believe if that's the only difference, they are essentially charging $50 for a wiring harness. Wait, yes I can.)
Thank you for any knowledge and input here.
http://www.autozone.com/autozone/par...707572_0_5320_
This is the Universal sensor, but it just appears to not come with the connector. Does my car not have that connector already and I can just use the miniplug it's got wired to it?
Notice:
http://www.autozone.com/autozone/par...5_0_1784_97999
This appears to be an O2 sensor that is applied before the catalytic converter and has that same miniplug, but comes with that connector. I'll buy whatever I need, it would just be cool to save around $50 if I can. ;D (and that said, I can't believe if that's the only difference, they are essentially charging $50 for a wiring harness. Wait, yes I can.)
Thank you for any knowledge and input here.
02-24-11, 12:02 AM
#15