P0426: Catalyst Temperature Sensor Range/Performance (Bank 1 Sensor 1)

What does P0426 mean?

P0426 is a diagnostic trouble code indicating "Catalyst Temperature Sensor Range/Performance (Bank 1 Sensor 1)". The sensor or component is providing readings, but they fall outside the expected operating range. The part may be degraded, contaminated, or experiencing intermittent issues affecting catalytic converter performance.

Symptoms you may notice

• Check engine light (MIL) illuminated on dashboard
• Rotten egg smell from exhaust
• Reduced engine performance
• Failed emissions test
• Engine overheating

Common causes

• Worn or contaminated catalytic converter component
• Vacuum leak or intake air leak
• Clogged filter or restricted flow
• Intermittent electrical connection issue

What should you do?

Schedule a diagnostic appointment at your earliest convenience. The vehicle is generally safe to drive short distances, but the underlying issue should be addressed to prevent it from worsening.