muragrove

My 92 LS400 has a bulb warning light that comes on a couple of times a week for a few minutes then goes off. The dealer said that this sensor measures lamp current and it probably means I have a bad connection. I've checked all the exterior lights that I can think of and they all work every time I look at them. Has anyone experienced this and if so, how did you find the bad bulb? Bill

I finally replaced my front oxygen sensor. There are two of them. One looked pretty new, the other looked old so I assumed that one had already been replaced by a previous owner and replaced the older looking one. Then reset the error codes and it worked!! I've only burned a 1/2 tank of gas since then but it looks like this may have increased my gas mileage about 20% as well so that's a bonus. Thanks for your help everyone. Bill

Mine doesn't work either and the dealer wants close to $200 just for a new key. He said the transmitter is probably bad since I've already replaced the battery and that didn't help. It works sometimes if I'm close to the car. Bill

Thanks. This weekend - under the car - replace the sensor! Bill

Dear LS400 Fan, Thanks for your note. Have you seen or replaced these sensors yourself to be able to give me a better location? Just knowing it is UNDER the car helps! As for why not replace both, since this is a DIY project, it's simply cost. I'm out of work right now and if I can save the cost of an expensive sensor, I need to do it. Bill

The dealer told me there are TWO Oxygen sensors in front of and another two behind the catalytic converter. How do I determine which one is bad or do they always get replaced in pairs? And how to tell which one causes error code 25? Bill

I finally checked my code and it is a 25 (lean air-fuel ratio). Based on what I read here and what the dealer told me, that means a bad O2 sensor. I went to buy one from a NAPA parts store and they told me I have two, one before and one after the catalytic converter. He also said they are simple to replace but it wanted $140 for one of them and $110 for the other so I'll look for another source for those. How do I find and access these? They sound simple to replace if you can find them! Bill

Hi. Thanks for the info. What 'books' are you referring to? I've been too busy to try this yet. Maybe tomorrow. No reason to be scared, it's just a car! Bill

Thanks Larry, Good tip about a CD based manual on Ebay. I never would have thought of that. He said he reset the sensor but I'll try doing it again. I just found (from a tip on the previous post) how to read my trouble codes and will try that this weekend when I have some time. I'll try to reset the light at that time as well. Bill

Thanks for pointing me to that site. I didn't know about it. The dealer already scanned it and cleaned my very dirty EGR valve for $160. Had I known how easy that was I might have done it myeslf. However when I got the car back the check engine light was STILL on. He told me that my O2 sensor needed replacing for $320 or it would not pass my state emission check. As it happens, I was on the way to get an emission check anyway so I rolled the dice, left the O2 sensor alone and it passed with flying colors despite what the dealer said. Now I would like to read those codes myself and confirm his diagnosis, and now that I have have some time, perhaps replace the sensor myself. How can I find out how many O2 sensors my 92 LS400 has and where they are located? Are they simple to replace? Any adjusting necessary once they are replaced? I had an O2 sensor go bad on a 93 Sedan Deville and the gas mileage immediately went to about half it's normal range. That isn't happening on this car.

Does anyone know how I can retrieve and read the engine diagnostic codes on my 1992 LS400? The check engine light recently came on but the car runs fine. I've already checked the gas cap.