Code P0420, engine warning 4LO blinking and Slip Warning

Tiny
ANDY MU
  • MEMBER
  • 2010 TOYOTA PRADO
  • 122,000 MILES
When I scan the warning code is P0420 which is to be exhaust catalytic converter 1. I change the sensor, but after 1 or 2 hours, the warning appears again. Please help me.
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Monday, August 2nd, 2021 AT 5:57 AM

1 Reply

Tiny
SQM
  • EXPERT
Hello,

Since you have changed the sensor with no change to the outcome, it is a possibility that the catalytic converter might not be performing efficiently.
As the Prado is not sold in the US I don't have the exact diagnostics, however it should be similar to the Landcruiser that sold in the US.

Here are the probable cause for that code:

DTC
P0420
Probable Causes
Air Fuel (A/F) Ratio Sensor Bank 1 Sensor 1
Front No. 2 Exhaust Pipe - Three Way Catalytic Converter (TWC) Front Catalyst and Rear Catalyst
Gas Leak From Exhaust System
Heated Oxygen (HO2S) Sensor For Bank 1 Sensor 2

I have include a diagnostics procedure for catalytic converter for your reference:

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter
https://www.2carpros.com/articles/bad-catalytic-converter-symptoms
https://www.2carpros.com/articles/catalytic-converter-replacement

Please let me know if you have any questions.

Thank you.
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Monday, August 2nd, 2021 AT 7:02 AM

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