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.
Looking for an estimate?
Got a quote to fix P0430?
Enter your car and the price — get an instant verdict on whether it's fair, with labor hours checked against industry book time.
Check My Quote Free →The fair price shows after you enter your quote · free, no signup
Don't have a quote yet? Get matched with a pro directly →
Looking for leads?
Get matched with local homeowners
Local contractor or shop in your area? We send you homeowners who already checked their quote and want a fair bid — no cold-calling, no signup.
Get Leads →Straight to the person who runs it · no signup
Related codes
Informational only — codes share symptoms across vehicles, so proper diagnosis on your specific car always comes first.