What this code means

The Bank 1 warm-up catalytic converter is not efficient during the warm-up period.

Symptoms

• Check Engine Light
• Failed emissions test

Common causes

• Worn catalyst
• Engine running rich during warm-up
• O2 sensor issue
• Exhaust leak

Diagnostic steps

1. Monitor catalyst temps during warm-up
2. Compare O2 sensor signals
3. Check for exhaust leaks

Repair notes

Replace warm-up catalyst if confirmed failed.

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