P0420 – 2001_TOYOTA_HIGHLANDER

Code : P0420
Make : 2001_TOYOTA_HIGHLANDER
Description : P0420 2001 TOYOTA HIGHLANDER Catalyst System Efficiency Below Threshold Bank 1
Possible causes :
– Faulty Three-way Catalyst Converter Bank 1
– Exhaust Tube
– Intake Air Leaks
– Faulty Oxygen (O2) Sensor
– Faulty Fuel injector(s)
– Leaking Fuel Injector (s)
– Faulty Spark plugs
– Improper Ignition Timing
– Faulty Engine Control Module (ECM)
– Dirty Air Filter
Solutions :
– Carry out a Reset via CarDiag
– Choose a better quality fuel
– Check that the tank cap is securely closed
– Check the oil level and add more if it is lower than MAX
– Restart an Automatic diagnostic via CarDiag
– If the fault persists, you can check the “Possible causes” listed above : visually inspect (by yourself (tutorials to come) or by a professional) the wiring harness and the associated connectors, check for damaged components, and look for broken, bent, pushed, or corroded connector pins.

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