Toyota Tacoma
P0421
The P0421 code indicates "Warm Up Catalyst Efficiency Below Threshold (Bank 1)" in a 2016-present Toyota Tacoma N300. This suggests that the catalytic converter is not functioning effectively during the engine's warm-up phase.
1 SolutionP-CodePowertrain
P
Error Code Type
Powertrain
Components
1 affected
Exhaust System
Symptoms
5 common
- •Check engine light illuminated
- •Decreased fuel efficiency
- •Engine stalling or rough idle
- +2 more
Most Affected Generations
1 generation
N300
1
Top Affected Components
1 component
Exhaust System
1
Severity Levels
1 level
high
1
Quick Facts
1
Total Solutions
1
Affected Components
5
Common Symptoms
1
Generations
All Solutions
Showing 1 of 1 solution for error code P0421 across all generations.