OBD-II · P0430
P0430 Code: Bank 2 Catalytic Converter — Before You Pay
Catalyst efficiency below threshold (Bank 2)
The short version
Usually drivable for months, but it fails emissions and can indicate real conversion loss worth investigating.
- Severity: Moderate
- Most common cause: Small exhaust leak ahead of the upstream sensor
- 5 diagnosis steps in order
- 4 symptoms tied to this code
Darker bars are the more common causes; bar length is the top expected repair cost. Start with the dark, cheap causes before the expensive ones.
Can I keep driving?
Usually drivable for months, but it fails emissions and can indicate real conversion loss worth investigating.
Symptoms
- Steady check engine light with normal performance
- Occasional sulfur smell from the exhaust
- Emissions test failure
- Downstream sensor swinging like the upstream one
Causes & repair cost
Small exhaust leak ahead of the upstream sensor
Most common$60 – $250
Lazy downstream oxygen sensor with no code of its own
Most common$110 – $350
Misfire or oil burning that damaged the substrate
Possible$200 – $900
Genuinely spent Bank 2 converter
Possible$400 – $2,200
Missing ECM calibration update
Rare$80 – $250
Leak repair $60–$250, downstream sensor $110–$350, and a compliant converter $400–$2,200 depending on the model.
Estimate the repair for your carDiagnosis steps in order
- Listen at cold start and look for soot marks indicating leaks
- Compare upstream and downstream traces — a healthy downstream trace is nearly flat
- Fix any misfire or oil consumption first
- Ask for an inlet/outlet temperature-differential test
- Check whether an official calibration update exists for your model
FAQ
What is the difference between P0420 and P0430?
Both are the same fault on different banks of a V engine; P0430 refers to Bank 2.
Do both codes together mean two bad converters?
Not necessarily; a shared cause such as a misfire or rich mixture harms both banks, and fixing it can clear both codes.
Can I pass inspection by clearing the code?
No; clearing resets readiness monitors to incomplete and the station rejects the car.
Is a used converter a good option?
It is risky; you cannot measure its remaining life and the code often returns. A new compliant unit is safer.
Related codes
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