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Toyota Aygo P0420 10minutes delay before O2HS2 output

  • aidan.cunningham
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3 years 4 months ago #56498 by aidan.cunningham
Toyota Aygo P0420 10minutes delay before O2HS2 output was created by aidan.cunningham
Hi there, apologies if this is not the correct subsection. I did use the search function to see if it was covered before.

I have a Toyota Aygo 1.0l 1KR-Fe 2017 with a common P0420 code for catalyst efficiency.

In diagnosing the issue I came across a curious behaviour that I’m not sure is normal or not. It takes 10 minutes before the heater circuit starts operating and the voltage on the signal line to drop from 1.57 volts to about 850mv.

Once the key is turned off, the time seems to reset and you must wait another 10 minutes before you can read any data or even scope this sensor. Sensor 1 gives a normal signal immediately.

Does this sound like normal behaviour? Is the ECU switching off the circuits until it presumes catalyst is up to operating temp?

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