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Why is my check engine light on after changing catalytic converter?
OBD Code P0420 means the catalyst system efficiency is below the threshold. If you spend $900 or more to replace the catalytic converter, you may discover the check engine light coming on again later. Some mechanics will tell you to try replacing the oxygen sensors first, to see if that solves the problem.
Can an aftermarket catalytic converter cause check engine light?
If you replace ANY of those stock cat pipes with either “offroad” (no cat) versions, or with aftermarket catalytic converters, you MAY get the P0420 “Check Engine” light (CEL). Also note that if your car is subject to emissions inspection, it WILL fail if there is an active CEL.
How long does it take for oxygen sensors to reset?
five minutes
Turn the ignition to the on position but do not turn on the engine (it will not start anyway). After five minutes, reinsert the fuse. The lamp of the check engine will blink and then turn off, indicating that your ECU has been restored.
What happens if my O2 sensor goes bad?
If your vehicle has a bad oxygen sensor, it could run irregularly or sound rough when it idles. A faulty oxygen sensor can impact your engine’s timing, combustion intervals, and other essential functions. You could also notice stalling or slow acceleration.
Can you replace the O2 sensor on a car?
Replace O2 Sensor and still get Check Engine Light On. Replaced O2 Sensor and still get Check Engine Light On. 2 different shops did reads on my check engine light codes, I even paid $100 for one of them to do a full test of all sensors to identify which one was bad.
Can a new oxygen sensor fix a catalytic converter?
However, I see questions all the time on auto forums asking if a new oxygen sensor will fix the problem. The answer is—almost never. What’s driving the issue is that everyone wants the cause of the P0420 to be a bad oxygen sensor so they don’t have to replace the expensive catalytic converter.
What happens if you replace the catalytic converter?
If you spend $900 or more to replace the catalytic converter, you may discover the check engine light coming on again later. Some mechanics will tell you to try replacing the oxygen sensors first, to see if that solves the problem. There are two of them, one before and one after the catalytic converter.
What does the OBD2 code mean on a catalytic converter?
Answer: The P0420 OBD2 code indicates that the efficiency of the catalyst system is below the threshold. But that doesn’t necessarily mean you have a bad catalytic converter. The code will happen if the upstream and downstream oxygen sensors indicate similar readings. They won’t match if the catalyst system is within a proper threshold.