RCRFAN3 Posted February 3, 2006 Share Posted February 3, 2006 I have a 98 LS400, 115,000 mi. extremely well maintained. All service intervals met. The check engine light came on after leaving the car running while I refueled. I disconnected the battery to turn the light off, drove another 300 miles;without the light coming back on, and refueled with the car running again (due to the cold weather). I drove 15 miles and the light came on again. The car runs flawlessly, with the fuel mileage around town being 21 MPG. I took the car to AutoZone to have them read the codes, and it came up a 0136; bank one, sensor two. I believe that means the O2 sensor after the catalytic converter, left side. Remember the car is still running flawlessly. The price for a direct replacement Bosch O2 sensor is $90, DIY. Does anyone have any history on this same problem or on the code that came up, just to make sure I have it right. I am the second owner of the car, since 70,000. The car has only ever used 93 octane Shell fuel. Any help would be appreciated. Jeff Quote Link to comment Share on other sites More sharing options...
SRK Posted February 3, 2006 Share Posted February 3, 2006 More than likely the code was tripped by taking the gas cap off with the engine running. That's a no-no for the emissions system. It is also a less than smart idea from a safety aspect. Quote Link to comment Share on other sites More sharing options...
VMF Posted February 3, 2006 Share Posted February 3, 2006 the thing is, there are sensors in the fuel system and there is a sensor in the fuel tank that measures the pressure. as you know not all fuel is being used by the engine so a big part of the fuel deleiverd to the engine goes back into the tank. electrical fuel pump maintains a certain pressure in the system and once you left the car running and opened the tank you triggered that pressure sensor to report the drop in pressure. just use any obdII scanner to reset the code and you will be fine. nothing went bad. Quote Link to comment Share on other sites More sharing options...
Arkansawyer Posted February 3, 2006 Share Posted February 3, 2006 Every time I fill up my '93 the car is running and this has never happened to me. Ima gonna say.......bad O2 sensor. There is a recent post about someone replacing the O2 sensors before he even got a CEL and the performance was much improved after replacement. IOW just because it is still running OK does not neccessarily mean the O2 is still good Quote Link to comment Share on other sites More sharing options...
nc211 Posted February 3, 2006 Share Posted February 3, 2006 Ark, That very well might be the case...I don't have a code book for your model year to tell you what exactly your CEL code means....but a 93' and an O2 sensor being bad doesn't seem too far fetched to me, especially if it's the original O2 sensor. But I do advise that you don't fill up anymore with the car running, as this will also trip your CEL like the other guys say. Or, it should anyway. If it's not, then maybe that is a clue to a pending problem? I though the 420 code was O2 sensor related? But that just might be for the Gen II LS400's. Have you called the dealership and asked what the code means on a 1993 model? I'm sure they'd be more than happy to tell you. But either way, I honestly don't think you'd be wasting your money on replacing the O2 sensor, even if it's not the problem. They just might be so old that they're ready for replacement anyway, and maybe you'll be heading off a bigger problem down the road by doing a "preemptive" strike repair. Oh man....I need to change my avatar, I'm starting to sound like him. Quote Link to comment Share on other sites More sharing options...
Arkansawyer Posted February 3, 2006 Share Posted February 3, 2006 RCRfan is the one who has the issue and it looks like he drives a '98. Still don't think filling up while having the car running will trigger an error code, but I've been wrong before......once :) Quote Link to comment Share on other sites More sharing options...
VMF Posted February 3, 2006 Share Posted February 3, 2006 RCRfan is the one who has the issue and it looks like he drives a '98. Still don't think filling up while having the car running will trigger an error code, but I've been wrong before......once :) it does trigger the error, if you will get the error code and decode it you will see for yourself. dealer told me not to fill it up with the car running. it is also mentioned in the factory repair manual. O2 sensor has nothing to do with the pressue in the fuel system. there are 4 o2 sensors in LS and all 4 have their own codes which are different from the code you get by opening the gas tank while the engine is running. Quote Link to comment Share on other sites More sharing options...
Arkansawyer Posted February 3, 2006 Share Posted February 3, 2006 I'm bowing out of this conversation. My car is running fine, I don't have any error codes and next week when I fill up with gas while the car is running(and not producing a CEL), I'll be thinking of you guys. ;) Quote Link to comment Share on other sites More sharing options...
VMF Posted February 3, 2006 Share Posted February 3, 2006 I'm bowing out of this conversation. My car is running fine, I don't have any error codes and next week when I fill up with gas while the car is running(and not producing a CEL), I'll be thinking of you guys. ;) the sensor was added in the second generation LS starting 95 and up Quote Link to comment Share on other sites More sharing options...
Arkansawyer Posted February 3, 2006 Share Posted February 3, 2006 Thank you. Quote Link to comment Share on other sites More sharing options...
cardona6569 Posted February 4, 2006 Share Posted February 4, 2006 Thank you. Hi: I got a 98 and yes the O2 sensor went bad. The car will run with no problems but the check engine light that came on. If you try to reset it just comes back as yours did. Replaced the sensor had no more problems. If you can do it for 90.00 you have a good deal the dealer charged me about 300.00 for labor and diagnostics. They also told me that once you replace it usually it does not come back. The only risk you are running is the one of ruining your Catalitic Converter. They could overheat and get damaged causing other problems. When you replace the sensor the car will spend less gas, because of the incorrect reading the bad sensor is giving the computer. It coud increase gas mileage about 1 to 2% better, about a mile more per galon city and 2 more in the highway. C. PR Quote Link to comment Share on other sites More sharing options...
VMF Posted February 4, 2006 Share Posted February 4, 2006 Thank you. Hi: I got a 98 and yes the O2 sensor went bad. The car will run with no problems but the check engine light that came on. If you try to reset it just comes back as yours did. Replaced the sensor had no more problems. If you can do it for 90.00 you have a good deal the dealer charged me about 300.00 for labor and diagnostics. They also told me that once you replace it usually it does not come back. The only risk you are running is the one of ruining your Catalitic Converter. They could overheat and get damaged causing other problems. When you replace the sensor the car will spend less gas, because of the incorrect reading the bad sensor is giving the computer. It coud increase gas mileage about 1 to 2% better, about a mile more per galon city and 2 more in the highway. C. PR there are around 200 different error codes and all of them would trigger the check engine light to come up. i dont see any connection between the starting of the topic and o2 sensor going back. unless you know the code that triggered the light you cant really say much. Quote Link to comment Share on other sites More sharing options...
branshew Posted February 4, 2006 Share Posted February 4, 2006 Still don't think filling up while having the car running will trigger an error code, but I've been wrong before......once :) It will in some newer cars. I'm w/ VMF on this one. My wife tried this in her VW and it threw a CEL on her as well. Also - definitely not a good idea from a safety point. Quote Link to comment Share on other sites More sharing options...
nc211 Posted February 4, 2006 Share Posted February 4, 2006 Oops...my bad...sorry amigo! My hooked-on-phonics hasn't arrived yet. RCRfan is the one who has the issue and it looks like he drives a '98. Still don't think filling up while having the car running will trigger an error code, but I've been wrong before......once :) Quote Link to comment Share on other sites More sharing options...
cardona6569 Posted February 5, 2006 Share Posted February 5, 2006 Thank you. Hi: This is my what my invoice from the dealer with full diagnostics says as follows: Code PO135, 02 sensor heater circuit malfunction Bank 1 Sensor 1. From reading his post he talks about: "The car runs flawlessly, with the fuel mileage around town being 21 MPG. I took the car to AutoZone to have them read the codes, and it came up a 0136; bank one, sensor two. I believe that means the O2 sensor after the catalytic converter, left side." Seeing the exposed evidence I believe without doubts that, yes he talks about a bad 02 censor and yes since is not the same one as mine it gives a little different code, 136 and mine a 135, but he has a bad 02 most likely. His car did not damage the same one as mine did. My car ran without any other issues just as his. Sincerely, C. PR Hi: I got a 98 and yes the O2 sensor went bad. The car will run with no problems but the check engine light that came on. If you try to reset it just comes back as yours did. Replaced the sensor had no more problems. If you can do it for 90.00 you have a good deal the dealer charged me about 300.00 for labor and diagnostics. They also told me that once you replace it usually it does not come back. The only risk you are running is the one of ruining your Catalitic Converter. They could overheat and get damaged causing other problems. When you replace the sensor the car will spend less gas, because of the incorrect reading the bad sensor is giving the computer. It coud increase gas mileage about 1 to 2% better, about a mile more per galon city and 2 more in the highway. C. PR there are around 200 different error codes and all of them would trigger the check engine light to come up. i dont see any connection between the starting of the topic and o2 sensor going back. unless you know the code that triggered the light you cant really say much. Quote Link to comment Share on other sites More sharing options...
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