P0430
System
Powertrain (Emissions)
Scanner required
Enhanced OBD2 scanner (live data graphs, freeze frame, battery voltage test)

Catalyst System Efficiency Below Threshold (Bank 2)

Understand P0430, common causes, and the right TOPDON scanner to diagnose it.

Same as P0420 but for bank 2 on V-engines. Both banks share exhaust on some vehicles — verify which converter and O2 sensors apply.

Common symptoms

  • Check engine light
  • Failed smog test
  • May appear with P0420

Typical causes

  • Failed bank 2 catalytic converter
  • Downstream O2 sensor bank 2
  • Exhaust leak
  • Engine running rich or misfiring on bank 2

What scanner do you need?

Enhanced OBD2 scanner (live data graphs, freeze frame, battery voltage test)

Use live data and freeze frame to confirm the fault before replacing parts. ABS, SRS, and network U-codes usually require a full-system scanner.

Diagnostic tips

  • Record freeze frame data when the code first sets
  • Clear the code only after fixing the root cause
  • Check for related pending codes that point to a common issue
  • Verify battery voltage is above 12.4V before chasing sensor codes

Recommended TOPDON scanners

Frequently asked questions

Can I diagnose P0430 with a basic code reader?
P0430 may set in the engine module, but related diagnostics often benefit from an enhanced or full-system scanner with live data and freeze frame.
Is it safe to drive with P0430?
It depends on the code and symptoms. Flashing check engine lights and misfire codes should be addressed immediately. Consult a professional if unsure.