Mechanics

ENGINE LIGHT P0420

2003 Toyota Corolla

Engine problem
2003 Toyota Corolla 4 cyl Front Wheel Drive Automatic 120000 miles

I have engine light on and diagnostics shows P0420. What to do.
Avatar
Vaqaskhan
December 26, 2007.




Code for poor catalyst efficency on bank 1

An oxygen sensor is no more good and should be replaced

The engine coolant temperature sensor is not working properly (change it first and see if code comes back)

Damaged exhaust manifold / catalytic converter / exhaust pipe (visually check over, if this and the first 3 come up negative change the converter.

Blackop555
Dec 28, 2007.


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