A P0420 diagnostic code on your 2023 Toyota Highlander indicates that the catalytic converter efficiency has dropped below acceptable levels. The 2023 Highlander introduced a new turbo engine option alongside the hybrid.
2023 Highlander Engine Options
- 2.4L Turbo 4-cylinder: 265 hp, single exhaust bank
- 2.5L Hybrid: 243 hp combined, single exhaust bank
Both engines use 4-cylinder single-bank configurations, eliminating the previous V6 option.
P0420 on a Newer Vehicle
A 2023 Highlander showing P0420 is relatively early for converter failure. Consider:
- O2 Sensor Issues: More likely than converter failure
- Exhaust Connections: May have loosened
- Manufacturing Variation: Rare converter issues
Warranty Coverage
A 2023 Highlander should be under full warranty including emissions.