Hi! I'm new here, and hoping I can learn about my older car's need for two oxygen sensors, and a couple of other parts. My son has a GS400 (1998) he is parting out, and has two pre-cat oxygen sensors; one for driver's side, and one for passenger side. Would those be parts I could use on my LS 430? I was told I have one bad sensor on top and one on the bottom. Not sure what that means!

My son also has the key with the lock/unlock buttons - mine was crushed before I bought this car - but I'm unsure if his can be programmed for my car. I'm not sure of the best way to search this site for the answer! If I looked for instructions for programming the key for an LS 430, 2001, would I be able to learn whether his key would be compatible, or programmable, for my car?

Also, a system check says I have 4 cylinders that are misfiring: # 2,4,6 and 8. A mechanic I consulted thinks this might have something to do with the oxygen sensors, for an entire bank of cylinders to be having a problem. My issue is that he quoted me a much higher price to replace the 2 oxygen sensors than the parts plus labor ($900 - $1000), so I'm unsure of this advice.

Lastly, the "check VSC" light just came on. Per the manual, I tried pushing the VSC button, to turn VSC off, but the "Check VSC" light still comes on!

Can anyone help or advise me?

 

To determine if oxygen sensors from a GS 400 would work on your LS 430, you need to compare the part numbers. That said, I would not install used oxygen sensors, especially since most of the expense is labor.

Regarding the interchangeability of key fobs - again, compare part numbers or ask a Lexus dealer.

Consult another mechanic concerning the cylinder misfires and/or install new oxygen sensors to see if they resolves the problem.

There are many threads about VSC, an answer for you may lie therein.

 

Possible, but unlikely.
There are 4 sensors, 2 for each bank of cylinders.
Bank 1 (Left) Sensor 1 is in the left header.
Bank 1 (Left) Sensor 2 is in the left exhaust after the first Catalyser.
Ditto for Bank 2 (Right).
The Sensor 1s are different left from right so make certain you get one with the correct wiring.
I paid about $80 for my Bank 2 Sensor 1 and it was an OEM Denso one.
It's not worth the effort to remove the ones from the GS at that price.

 

Check VSC will definitely come on if there are engine misfires. My top right O2 sensor's heating element failed about 10 years ago, I vaguely recall this caused a Check VSC message as well.

The Vehicle Stability Control cannot operate if the engine does not function exactly like it should. The engine, braking, and steering systems need to be operating properly in order for VSC to work.

Don't bother with a used O2 sensor, just buy new ones. The Denso part is equivalent or even exactly the same as the Lexus part, and typically less expensive.
B1S1 O2 Sensor Denso part # 234-4138, Lexus part # 89465-50120
B2S1 O2 Sensor Denso part # 234-4630, Lexus part # 89465-50130
Both rear O2 Sensors are the same, Denso part # 234-4167, Lexus part # 89465-50140

Key programming requires a Toyota/Lexus-specific scanner/computer, you will need to take it to any Toyota or Lexus dealership. There is also a limit on the number of different keys that can be stored in the LS430, I believe it that # is 6, but you could also erase all previous keys and reprogram from scratch. You usually need a Master Key to reprogram, which is the main key that came with the car when new.

 

Thank you so much! You've provided much needed information, and I'll definitely take the car to a Toyota/Lexus dealer to learn more.

The real problem I have with expense is that I bought this car from my sister-in-law for $1000, after hitting a deer and totaling my small SUV.. I thought of it as an "interim" car, yet it is so wonderful to drive, I am definitely willing to spend money to repair important parts. I have to remind myself that every dollar I spend on this car is a dollar less I have to purchase an SUV, which I need for transporting equipment. And, I think my son is interested in owning the car when I do purchase another car, so maybe I should think of it as investing in a car for him. (Or, ask him to help with expenses, since the car will ultimately be his)!

 

Thank you so much! I will contact my son about the part numbers on his equipment, although I read in another post that I shouldn't put used equipment on this car.

I really appreciate your response. SO helpful!

 

Thank you! The mechanic who recommended replacing the oxygen sensors first told me it wasn't that necessary to replace them. However, when we learned about the cylinders misfiring, he thought there might be a connection. I agree that it would be costly to replace the cylinders, yet I'm not sure what will happen if I don't. Will I be damaging the engine by driving it when the cylinders are misfiring?

I'm going to take it to a Toyota/Lexus dealer for their opinion of the problems, however, my experience with dealers has often been that they try to make the situation sound more drastic, and the recommended repairs are numerous, and at a premium cost. At least I can get an expert's opinion, however, and hopefully I'll be able to make a better decision!

 

Yes, it is bad for the engine to operate while misfiring. It is very bad when half the engine is misfiring. As I mentioned, the O2 sensors are related to the Check VSC, but I highly doubt the O2 sensors are related to the misfiring (as in bad O2 sensors don't cause misfires). However, if the engine was misfiring for a long time, it could have caused damage to your O2 sensors, and in any case, misfires do cause damage to your catalytic converters (there are 3 catalytic converters in the LS430).

I don't think replacing the cylinders/pistons/valves is the solution to your misfires. If your son wants to "inherit" your car, you should make him learn how to fix it and do the labor for you - that would be a fair tradeoff. Since the car is already broke, he could use your car as a platform for learning, which is better than learning on a brand new $80-100K car. I would start a proper computer diagnostic (Techstream), you will need a throwaway laptop (Windows XP works fine), and a $30 cable from eBay/China. Then make a list of the trouble codes, read the first few paragraphs in the service manual for each trouble code to make sure you take care of related codes in the proper order, then basically follow the service manual troubleshooting steps.

I would also start with checking the wire harness on that bank of cylinders, ensuring the spark signal is being sent to the ignition coils, then checking that the ignition coils actually fire, then checking that an attached spark plug actually fires. Then check the fuel delivery system (fuel rail, fuel pressure dampener, fuel injectors). Whatever codes you have will likely point you this direction. You do have to be mechanically-inclined to do this work, and if your son wants to learn how, this is a great opportunity to do so.

Otherwise, if you want to get the car up and running ASAP and don't mind paying for legitimate parts and labor, your local Toyota/Lexus dealer should be competent enough to fix whatever problem you throw their way. I would not take it to an independent shop unless they are experienced with Toyotas, and preferably experienced with LS430s. One option you have is to pay the Toyota/Lexus 1 hour diagnostic fee, after which they will give you a printout of all trouble codes, issues found, and parts and labor required. You could then post a picture of that printout here and we can tell you if it sounds reasonable or not, and what your son could do at home versus what requires dealership tools to do.