We get several customers a week coming in asking to replace their catalytic converters, as they were told they were bad and needed replaced. Not only is this expensive, especially if you require a direct fit cat but it could also be unnecessary.
You’re pulling a P0420 code? – This is a common code that can will pull from all makes and models post 1996 and newer. Before we talk about replacing a catalytic converter we check each sensor to make sure they are in working order, we check for exhaust leaks, check the cat itself. We run a live data feed at idle, and do a heat check see if there is a 100 degree difference on the cats.
Come visit us before you replace your cats and we will check them for you.
Possible causes for the code:
- Leaded fuel was used where unleaded was called for (unlikely)
- A damaged or failed oxygen / o2 sensor
- Downstream oxygen sensor (Ho2S) wiring damaged or connected improperly
- The engine coolant temperature sensor is not working properly
- Damaged or leaking exhaust manifold / catalytic converter / muffler / exhaust pipe
- Failed or under performing catalytic converter (likely)
- The oxygen sensors in front and behind the converter are reporting too similar of readings
- Leaking fuel injector or high fuel pressure
- Cylinder misfire oil contamination