What does Bank 1 on a P0420 mean?
The P0420 “Catalyst System Efficiency Below Threshold (Bank 1)” DTC is an indicator of problems with the Bank 1 catalytic converter (view on Amazon). This means that the catalytic converter is damaged, worn out, or degraded. Bank 1 means the code is referring to the side of the engine where the number one cylinder is located.
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.
What does P0420 mean on a catalytic converter?
P0420 means that the efficiency of the catalytic converter is below the threshold. The ECM uses two O2 sensors, one in the front and one in the back of the catalytic converter to measure the efficiency. If the efficiency is low, the P0420 code will be triggered.
Why does my Honda Accord have a P0420 code?
Then, the Check Engine Light is triggered, and you get a P0420 engine code. Many owners have reported P0420 for the following makes: Honda (especially on a Honda Accord), Chevrolet, Nissan, Ford, and Toyota. A faulty catalytic converter is the most frequent cause of a P0420 code. Common issues that can cause the P0420 code include:
What is the OBD II fault code P0420?
OBD II fault code P0420 is a generic trouble code that is defined as “Catalytic converter system, bank 1 – efficiency below threshold” and is set when the PCM (Powertrain Control Module) detects a condition in which the efficiency of the catalytic converter that serves Bank 1 has fallen below a minimum allowable threshold.
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.
When does the ECM set the P0420 code?
When the ECM/PCM sees the downstream O2 sensor switching at or near the same rate as the upstream O2 sensor, it sets the P0420 code. What Does the P0420 Code Mean?
What causes the P0420 oxygen sensor to read lean?
If the upstream and downstream oxygens sensors are both switching from rich to lean, that’s the sign of a dead catalytic converter. 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.