Why do some Prius owners experience a Check Engine Light related to emissions?

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Why do some Prius owners experience a Check Engine Light related to emissions?

A faulty oxygen sensor, catalytic converter, o r EVAP system leak can trigger the Check Engine Light CEL. Discussing how to diagnose and fix these issues can help Prius owners avoid costly repairs.

Zarnish asked on 13 Feb 2025 12:35:38 pm

1 Answer

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Car Mechanic Expert - on 13 Feb 2025 12:44:08 pm

Common reasons for the Check Engine Light CEL related to emissions include:

Faulty Oxygen Sensor: The oxygen sensor monitors the exhaust gases and helps adjust the air/fuel mixture. A malfunction can cause increased emissions and poor engine performance.
Catalytic Converter Problems: If the catalytic converter fails, it may cause the CEL to activate due to an inability to properly filter emissions.
EVAP System Leaks: Leaks in the Evaporative Emission Control EVAP system, which controls fuel vapors, can also trigger the CEL.

Diagnosis:

Use an OBD-II scanner to read the error codes and determine the exact issue.
Fix o r replace faulty components such as oxygen sensors o r the catalytic converter as needed.