P0430 Code

The catalytic converter is a part in your exhaust system that changes harmful gases into cleaner ones before they exit the tailpipe. Certain engines have two rows of cylinders, known as banks, and bank 2 is the side opposite the first cylinder.

An oxygen sensor checks the oxygen level in the exhaust. There's one ahead of the converter and one behind it. The code gets set when the two sensors show similar oxygen readings, which points to the converter not working properly, according to OBDeleven.

P0430 is essentially the bank 2 counterpart of P0420. O'Reilly explains that P0420 flags the bank 1 converter while P0430 flags the one on bank 2.

A California shop says the most frequent cause is a worn-out catalytic converter, particularly on older vehicles. Other problems can set off the code or harm the converter:

• A fuel tank cap that isn't tight
• A bad oxygen sensor on either side of the converter
• Damaged or poorly fitted wiring going to the rear oxygen sensor
• A leak in the exhaust, because even a tiny one can throw off the readings
• An engine running rich, which means it's burning more fuel than the air coming in can handle
• Spark plugs or ignition coils that are worn out
• Oil or coolant leaking into the engine's cylinders
• Engine computer software that's out of date

The sources don't fully agree. OBDeleven rates P0430 as moderately severe and says you can drive short term but should see a mechanic soon; O'Reilly recommends not driving until the problem is diagnosed.

Keeping on driving with this code for too long can also mean failing a smog or emissions test.

The sequence matters here, because fitting a new converter before the actual cause is sorted out can ruin that converter as well.

1. Give the fuel cap a firm twist until it clicks, since a loose one is a known trigger and checking it is free.
2. Get the exhaust looked at for leaks, because even a small one can throw the sensor readings off.
3. Have both oxygen sensors checked, along with the rear sensor's wiring, since a faulty sensor can make a healthy converter look bad.
4. Have a mechanic look at the spark plugs and ignition coils, and check whether the engine is running rich.
5. Ask if there's a software update for the engine computer.
6. If testing shows the bank 2 converter has failed, sort out any root cause first, then put in the new converter.
7. Once the repair is done, clear the code and drive for at least 15 minutes to let the engine warm up fully before you scan it again.

OBDeleven says fixing P0430 can cost anywhere from a few hundred dollars up to several thousand. These repair prices are published averages, and a local shop may quote higher or lower.

Every average comes from RepairPal.

P0430 can cause your car to fail an emissions test. In places where the inspection is a plug-in computer check, a glowing check engine light means the car fails.

Once a repair is done, the car still needs to complete its own self-checks, known as readiness monitors. If you've driven less than about 200 miles since clearing the codes or changing the battery, the self-checks may still be unfinished, and mileage alone doesn't confirm that the car is ready for testing. Most states follow EPA rules here: a 2001 or newer car can still be tested with 1 monitor not ready, while a 1996 to 2000 car is allowed 2.