help on code po420
11-13-2008, 04:46 PM
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Re: help on code po420 (forced97)
Originally Posted by forced97
cat code clear and see if comes back if it does time for a new cat converter
In truth a P0420 is Catalyst System Efficiency Below Threshold (Bank 1). Your front side O2 sensor is having issues. Have you modified the car at all? If not, this code can sometimes come on for a number of reasons most of which are flukes. Reset the code, or just drive for a few days and see if it goes out on its own. If there is no real problem, the ECU will realize this and reset the code on its own. Check to make sure the front side O2 sensor is secured into the catalytic converter and that the wires for said sensor were not disconnected. There are many possible results but the last of which and the most unlikely is the need of a new converter.
11-20-2008, 08:21 PM
#7
Honda-Tech Member
Okay, so much for the generalized, no help answers.
In truth a P0420 is Catalyst System Efficiency Below Threshold (Bank 1). Your front side O2 sensor is having issues. Have you modified the car at all? If not, this code can sometimes come on for a number of reasons most of which are flukes. Reset the code, or just drive for a few days and see if it goes out on its own. If there is no real problem, the ECU will realize this and reset the code on its own. Check to make sure the front side O2 sensor is secured into the catalytic converter and that the wires for said sensor were not disconnected. There are many possible results but the last of which and the most unlikely is the need of a new converter.
In truth a P0420 is Catalyst System Efficiency Below Threshold (Bank 1). Your front side O2 sensor is having issues. Have you modified the car at all? If not, this code can sometimes come on for a number of reasons most of which are flukes. Reset the code, or just drive for a few days and see if it goes out on its own. If there is no real problem, the ECU will realize this and reset the code on its own. Check to make sure the front side O2 sensor is secured into the catalytic converter and that the wires for said sensor were not disconnected. There are many possible results but the last of which and the most unlikely is the need of a new converter.
The front sensor is the A/F sensor not an o2 sensor and has nothing to do with the cat. The PCM uses this sensor to determine proper fueling in order to maintain stoich.The rear sensor is the o2 sensor and its sole purpose it to monitor the cat. This is the sensor that will set a code when the cat is no longer effecient or in some cases it will set a false code because the sensor itself is faulty...
Last edited by DCFIVER; 11-21-2008 at 08:18 AM.
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