Why is a P0420 trouble code never a bad oxygen sensor?

Why is a P0420 trouble code never a bad oxygen sensor?

NOTE: This is why a P0420 trouble code is almost never a bad oxygen sensor — because the ECM has already tested the downstream sensor. If it isn’t responding properly, it will set a trouble code. The same applies to the upstream sensor.

Are there any other codes associated with Hyundai P0420?

Do not overlook other codes that are paired along with P0420. Hyundai codes P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308, P0174, and P0171 can give false data readings that create conditions which trigger code P0420. If any other codes are present, they should be addressed first.

What causes a P0420 to read a steady lean condition?

An exhaust system leak really screws up the P0420 testing routing. An exhaust leak near the upstream sensor can cause the downstream sensor to read a steady lean condition. The ECM would interpret that as a bad catalytic converter.

What causes an oxygen sensor to set trouble code?

A leaky exhaust pipe obviously can let exhaust gases out of the pipe at the leak. But air can also be sucked into the pipe at the same leak. If that leak is upstream of the sensor, it will see the extra oxygen and set a trouble code. This is a costly repair, but common with a p0420 code.

Do not overlook other codes that are paired along with P0420. Hyundai codes P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308, P0174, and P0171 can give false data readings that create conditions which trigger code P0420. If any other codes are present, they should be addressed first.

What does it mean when your oxygen sensor says P0420?

Oxygen sensors are only a part of a greater system, meaning if the p0420 code (or p0141, or p0135) is thrown, that doesn’t necessarily indicate the oxygen sensors need replacement. Rather, there could be something else in that system does that’s causing the oxygen sensors to appear faulty.

A leaky exhaust pipe obviously can let exhaust gases out of the pipe at the leak. But air can also be sucked into the pipe at the same leak. If that leak is upstream of the sensor, it will see the extra oxygen and set a trouble code. This is a costly repair, but common with a p0420 code.

Why is the O2 sensor on my car not working?

Wires that are broken, melted against the hot exhaust pipes, or corroded, will give erratic or missing readings. Any of these can cause one or more cylinders to misfire. Because the oxygen in that cylinder isn’t burned up, the extra oxygen in that cylinder winds up passing over the O2 sensor.

NOTE: This is why a P0420 trouble code is almost never a bad oxygen sensor — because the ECM has already tested the downstream sensor. If it isn’t responding properly, it will set a trouble code. The same applies to the upstream sensor.

What does a P1000 DTC mean on a Jaguar?

A P1000 DTC in Jaguars means that the trouble codes have been recently cleared but not all of the drive cycles have been completed. If you note a P1111 DTC after clearing the codes, then that means that the drive cycles have been completed.

What does P0420 mean on a catalytic converter?

Here’s the official definition of a P0420 trouble code: P0420 Catalyst System Efficiency Below Threshold (Bank 1). What the code is telling you is that the catalytic converter has failed an efficiency test. In 99.5% of the cases, this code means that the catalytic converter itself is bad and must be replaced.

An exhaust system leak really screws up the P0420 testing routing. An exhaust leak near the upstream sensor can cause the downstream sensor to read a steady lean condition. The ECM would interpret that as a bad catalytic converter.

Here’s the official definition of a P0420 trouble code: P0420 Catalyst System Efficiency Below Threshold (Bank 1). What the code is telling you is that the catalytic converter has failed an efficiency test. In 99.5% of the cases, this code means that the catalytic converter itself is bad and must be replaced.

What does P0420 code mean on catalytic converter?

This sensor checks the performance of the catalytic converter, making sure it scrubs the last vestiges of pollution from your exhaust. Oxygen sensors are only a part of a greater system, meaning if the p0420 code (or p0141, or p0135) is thrown, that doesn’t necessarily indicate the oxygen sensors need replacement.

What does OBDII P0420 mean on a MDX?

WIth the MDX, OBDII P0420 is often caused by a bad oxygen sensor, but there can be other causes as well. Jumping straight to replacing the O2 sensor can cost you time and money. P0420 is the most common OBDII code there is. P0420 is a OBDII trouble code. The code technically stands for:


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