Check Engine Codes / P0430
P0430 Code
Catalyst System Efficiency Below Threshold (Bank 2)
What it means
Identical to P0420 but on the other bank of a V6/V8 engine. Same caveats: sensors and leaks mimic a bad cat.
Can you keep driving?
Yes, same as P0420.
Common causes
Listed most-common first. Fix cost depends on which one it turns out to be — check your quote free below.
⚠️ Don't get ripped off
Same rip-off pattern as P0420 — cat replacement quoted without ruling out the far cheaper sensor first. On V-engines, also confirm they've identified the correct bank before replacing anything.
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Related codes
Informational only — codes share symptoms across vehicles, so proper diagnosis on your specific car always comes first.