MasterTuning Fault code dictionary (DTC)

P0430 — Catalyst efficiency below threshold (bank 2)

Severity: Warning Can you drive? Yes, no known limitation Make: All makes (OBD-II standard)
MeaningOn the second bank the two lambda sensors read values that are too similar: that side's catalyst has stopped working. Same reasoning as P0420, on the other bank.
FamilyPowertrain (P)

Typical symptoms

Engine warning light on
No driving symptoms in most cases
Problems at the emissions test
Rotten egg smell in some cases

Common causes

Catalyst worn out by mileage
Aged rear lambda sensor
Exhaust leak upstream of the catalyst
Oil consumption or rich mixture that ruined it

What to do

Before ordering a catalyst, rule out the rear sensor and exhaust leaks, which give the same code at a fraction of the cost. And find the cause: a new catalyst on an oil-burning engine will not see the year out.

Frequently asked questions

What does code P0430 mean?

Catalyst efficiency below threshold (bank 2). On the second bank the two lambda sensors read values that are too similar: that side's catalyst has stopped working. Same reasoning as P0420, on the other bank.

Can I keep driving with code P0430 active?

Yes, no known limitation

Common causes — P0430

Catalyst worn out by mileage Aged rear lambda sensor Exhaust leak upstream of the catalyst Oil consumption or rich mixture that ruined it

How do you fix code P0430?

Before ordering a catalyst, rule out the rear sensor and exhaust leaks, which give the same code at a fraction of the cost. And find the cause: a new catalyst on an oil-burning engine will not see the year out.

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