What causes an oxygen sensor to set trouble code?

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.

What happens when you change the O2 sensor?

The O2 sensor then sends information to the electronic control unit, or ECU, the vehicle’s computer. The ECU then adjusts the air-to-fuel ratio to optimize the fuel combustion. Sometimes an O2 sensor fails, and you need to replace it.

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.

When do you need an oxygen sensor in a car?

You May Need an Oxygen Sensor Or You May Need Something Else Entirely When check engine lights are scanned, a p0420 code is a very common result. It’s actually a generic code, meaning it can be thrown from any vehicle after 1996.

What can cause an O2 sensor to set a different code?

There are also some other possibilities such as an internally leaking EGR system. This will typically set a separate code. A leak in the exhaust system before the (O2) sensor will also cause incorrect readings. The only other possibilities are wiring issues, and computer concerns.

Why did my check engine light come back on after replacing O2 sensor?

Fiance’s dad cleaned out the mass air flow sensor and ran the car a bit more with the old O2 sensors on and the car was running great again, but check engine light came back on with same old codes. I returned the O2 sensor that had the high resistance reading than spec and got a new one, replaced them.

When do you Know Your oxygen sensor is bad?

An OBDII code checker identifies defects in the exhaust system of the car. If your oxygen sensor has failed, the code checker will generate a diagnostic trouble code that specifically indicates your oxygen sensor is bad. The unheated 1 or 2 wire O2 sensors, used in vehicles from mid-1970s through early 1990s, replace every 40,000 to 50,000 miles.

When to reset the ECU after changing an O2 sensor?

Sometimes an O2 sensor fails, and you need to replace it. Once you’ve replaced your vehicle’s O2 sensor, you’ll need to reset the ECU so it can properly gather information from the new O2 sensor.

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