Check engine light and Check VSC codes on, can anyone give me some advice-lexus techs
 

Ok so I have a 2001 LS430 and I have done a search and have not found any specific answers to my problems. OK so like the title says, first I have a check engine light is on. I have check the codes and they are 420 and 430. So I thought it would the the O2 sensors before the catalytics and so I bought them new from Lexus and install them, cleared the codes, drove the car for about 30 mins and then bam, the check engine light comes back on and pulls the same codes. I was about to change my rear O2 sensors then the catalytic converters if I had to but I wanted to see if anyone here could help me figure out what the problem is. I really hope that it is not the cats because they are pretty pricey. Does anyone offer aftermarket direct replacement for the cats? Any info would greatly be appreciated. Oh I also noticed that my tank average has been decreasing. I only get about 14.5 -16 mpg on Tank Average.

Second problem is that my VSC light comes on only after I start rolling forward or backwards about 5 feet. Basically when I turn my engine on there is no Check VSC warning or anything. Then I start moving about 5 feet then the Check VSC words come on in the info center, my red triange with exclamation mark comes on and the my "VSC OFF" light come on. I try to turn it off but nothing happens. I also try to turn off the VSC before I start moving but the samethings happens. Anyone have any ideas what the problem could be. I would really like to get rid of my christmas lights inside the car. Thanks

Henry

my vsc did the same thing,the reason was because i cleared all the code in the computer. i had to paid afriend of mine 100$ to hook it up to his lexus hand held computer and reprogram it.hope this help

Hmm, that makes sense. It turned on right after I left autozone and they just hooked up a scanner to it. So you had to get a lexus tech to reprogram it using there scanner tool? Let me know. Thanks

Henry

Emmisions are warranty for 8 years/100,000 miles right?

80,000 last time I checked.

yeah he re calibrate the speed sensor and the vsc problem went away.....becareful with those scanners

Sometimes, it is because those sensors are dirty, I cleaned them up last week on my RX and noticed a little pickup.

:uh: nothing to do with dirt

I am sorry, those sensors can get dirty and will cause issues. Calibration is another thing entirely.

My check engine light and vsc light has come on twice so I disconnected the neg cable to clear the lights then took it to the dealer and they found a bad gas cap. The tech said that it had no fault codes..It ran fine even with the lights on...

Well, I tried unplugging the battery for about 15 mins and the VSC code came right back once the car started moving. Anyone else with any ideas. I have not tried to get it recalibrated yet. Thanks in advance.

Henry

The check engine light will come on every time until you fix the problem code. By unhooking the battery cable you clear the memory for a short term until the sensors finds the problems again and the CEL (check engine light) comes on again. The OBDII scanner will detect the code and can also clear the check engine light by erasing the error codes. After a few miles the CEL will come on again until the problem is solved. A loose gas cap could also trigger the CEL as well as the O2 sensors. The OBDII scanner will tell you exactly what area is the problem on your readout. Here are the error codes below for 420 and 430. The problem does not look like your O2 sensors are bad. O2 sensors code errors are between P0130-P0167. Yours is something different. Hope this helps.

P0420 Catalyst System Efficiency Below Threshold (Bank 1)
P0430 Catalyst System Efficiency Below Threshold (Bank 2)

Henry,
I didn't know you have a Lexus. Anyway, You rarely see both cat goes out at the same time. I've seen them both go in a matter of the same week. If you have access to scope or Lexus scanner. You know need to scope wave pattern before and after the cat. The front sensor is not the 02, it's the A/F sensor. If the wave pattern look about the same before and after cat sensor, you have a bad cat. I believe you replaced the front sensors? Have you test the black and red wire? This wire has constant 12v when ignition key is ON. Don't just swap out the parts... Test them !!! Let me know If you need any further help. If the cats are bad, I wouldn't bother with the aftermarket junks. Lexus cats aren't cheap but it won't give the same code again. I will be in the Houston area next week for a business trip, Let me know if you need further help. BTW, How is your supra? I'm sure you know stephane the 3.5L engine. He is a good friend of mine.
Regards,
JPI

Hey Jason,

Yeah I actually have 2 Lexus (GS400 and LS430). I just sold the SC300. Anyways, I don't believe I have access to a scope. I will test the black and red wires on the rear O2. Thanks for the offer on the help. I might need it when you come down. My supra will be done this week and is scheduled to get tuned next week I hope if all goes well. Yes I know Stephane and have seen his 3.5L block, it did not look good when I saw it. ;) Let me know when you are in town.

Henry

To correct the problem, I unplugged the battery, and replaced the spark plugs. I haven't seen the problem since.:D