P0420 Fault Code — Catalyst Efficiency Below Threshold (Bank 1)

Severity: 🟠 High — diagnose within 1–2 days

Catalytic converter not cleaning exhaust enough — most-searched engine code.

Can You Drive With This Code?

Yes. Yes, you can drive — there's no mechanical risk. But you'll fail PUC / emissions test, fuel economy drops, and ignoring it long enough will destroy the cat (₹35k–1.5 lakh part).

Common Symptoms

Common Causes

How We Fix It

Catalytic converter cleaning (₹3,500-₹8,000) or replacement. We do ultrasonic cleaning that restores 90%+ efficiency.

Repair Cost in Hyderabad

₹4,500–₹1.45 lakh — Front O2 sensor ₹4.5k–12k; catalyst cleaning ₹6.5k–14k; new cat ₹35k–1.45 lakh.

Frequently Asked Questions

What does P0420 mean?

P0420 (Catalyst Efficiency Below Threshold (Bank 1)) means Catalytic converter not cleaning exhaust enough — most-searched engine code. Common symptoms include check engine light, bad mileage, failed emissions test.

How much does P0420 repair cost in Hyderabad?

At GarageNation Hyderabad, P0420 repair typically costs ₹4,500–₹1.45 lakh. Front O2 sensor ₹4.5k–12k; catalyst cleaning ₹6.5k–14k; new cat ₹35k–1.45 lakh. We always diagnose first and give a fixed quote before any work begins.

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