What is your question?
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What is your question?
Ive heard that a P0420 error reading in my car requires the ECM to be flashed...True or not? SHould it be my first step before messing with o2 sensors and cat?
1 Reply
That's probably unlikely, but you could call your local Toyota dealership and ask whether or not Toyota has any software upgrades for your model. They can tell you if the factory has released an update to address problems. It's much more likely that you have an actual fault in your system and need a repair. A good diagnostic technician is the way to go.