P0430

What it means

P0430 means the engine control unit has judged that the catalytic converter on bank 2 is not cleaning the exhaust as well as it should. It compares the signal from the oxygen sensor before the catalyst with the one after it, and a rear sensor that switches too much like the front one suggests poor oxygen storage. Bank 2 is the side of a V or flat engine that does not hold cylinder 1, so this code only applies to engines with two exhaust banks.

Symptoms

• Engine warning light on
• Usually no change in how the car drives
• Possible failed emissions test
• Slight loss of fuel economy in some cases
• Rotten egg smell from the exhaust if the catalyst is failing
• Reduced power if the catalyst is badly blocked

Possible causes

• Worn or contaminated catalytic converter on bank 2 with reduced oxygen storage capacitylikely
• Exhaust leak before or around the bank 2 catalyst or rear oxygen sensor, giving false readingspossible
• Faulty or slow bank 2 downstream oxygen sensor, or damaged sensor wiring or connectorpossible
• Engine misfire or rich or lean running on bank 2 that has overheated or contaminated the catalystpossible
• Oil or coolant entering the combustion chamber (worn rings, valve seals or head gasket) contaminating the catalystpossible
• Faulty bank 2 upstream oxygen sensor giving poor fuel controlrare
• Outdated control unit software affecting catalyst monitoring (model dependent)rare

How to diagnose

1. Read all stored and pending codes and the freeze frame data, and note any misfire, fuel trim or oxygen sensor codes that need fixing first.
2. Check the service history and look for signs of oil burning, coolant loss or previous misfires.
3. Inspect the exhaust from the manifold to the rear sensor for leaks, cracks, blown gaskets and damage, and check the bank 2 sensor wiring and connectors.
4. Check long and short term fuel trims on bank 2 at idle and at steady speed to spot lean or rich running.
5. Watch the live bank 2 upstream and downstream oxygen sensor signals. A healthy downstream sensor stays fairly steady, while one that mirrors the upstream sensor points to a tired catalyst.
6. Check for misfires, and inspect spark plugs on bank 2 for oil, coolant or fuel fouling.
7. Test the oxygen sensor heater circuits and response, following the manufacturer's procedure for your model.
8. Check for any software updates or technical bulletins for the model, then confirm the repair with a drive cycle and monitor readiness.

How to fix

• Repair any exhaust leaks around the bank 2 catalyst and sensors.
• Replace a faulty bank 2 oxygen sensor or repair damaged wiring and connectors.
• Fix the root cause of any misfire, fuel trim fault, or oil or coolant consumption before fitting a new catalyst.
• Replace the bank 2 catalytic converter with a suitable approved part once other causes are ruled out.
• Apply a manufacturer software update only where a bulletin identifies outdated calibration as the cause.

Can I keep driving?

This code for other makes

• P0430AudiDefective Catalytic Converter, Internal engine damage resulting in high oil consumption and or a leaking Head Gasket has damaged the Catalytic Converter

Nearby codes

• P042FGenericEGR A Control Stuck Closed
• P0431GenericCatalyst 1 Efficiency Below Threshold Bank 2