How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Ron Z. Your Own Question
Ron Z.
Ron Z., - Lexus Tech -
Category: Lexus
Satisfied Customers: 18339
Experience:  18+yrs experience. State Inspector and Lexus Diagnostics
18617752
Type Your Lexus Question Here...
Ron Z. is online now
A new question is answered every 9 seconds

Traction control light stays on, code p0420, 2000es300, I am

Customer Question

traction control light stays on
JA: Do you know the code? Did you check the fuses?
Customer: code p0420
JA: What is the model/year of your Lexus?
Customer: 2000es300
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: I am a car dealer and I just sold this car and it never had this problem before
JA: Anything else you think the mechanic should know?
Customer: what do the codes mean
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Lexus Mechanic about your situation and then connect you two.
Submitted: 8 months ago.
Category: Lexus
Expert:  Ron Z. replied 8 months ago.

Unfortunately, the P0420 is a fairly straight forward code, and a fairly common problem. This code points to a failing Catalytic Converter (for Bank1 - this vehicle has 2 Converters). The Oxygen Sensors measure the amount of emissions in the exhaust going into, and then out of the converter. When they see that the converter is not "cleaning" the exhaust enough to meet specs, the Converter is deemed "below threshold" and the P0420 is set. Make sure there are no current cylinder misfires. Make sure there are no leaks in the exhaust system. Which, if there were, you should be able to hear. Sounding like a repeating "tick" or "puff" from the exhaust. Usually more predominate when the engine is cold. Make sure to include the exhaust manifold when checking for leaks/cracks. If these check ok, then most commonly, the Converter is "on it's way out" and will need replacement in the near future. Keep in mind, you will need a replacement converter that meets specs. Those "universal" or "discount" converters sold at some after market parts stores do not meet specs, and will not cure a P0420. If you found this answer helpful, please help me by leaving a rating using the "stars" at the top of the page or click 'accept'.
Rating or accepting my answer does not cost you extra. It allows me to be credited for this Q&A.

Expert:  Ron Z. replied 8 months ago.

If you have any questions or would like more information, please feel free to ask!

Customer: replied 8 months ago.
COULD THE TIRES BEING MISMATCHED BUT ALLTHE SAME SIZE MAKE A DIFFERENCE
Expert:  Ron Z. replied 8 months ago.

The tires being mismatched could set the traction light, however, if you are getting a "P0420" - this is a failing Catalytic Converter. Very well known fail item. Very straight forward code.

If you found this answer helpful, please, do the right thing and help me by leaving a rating using the "stars" at the top of the page or click 'accept'.
Rating or accepting my answer does not cost you extra. It allows me to be credited for this Q&A.
If you cannot rate or do not see where to rate, please let me know!

Related Lexus Questions