P0420 Code AGAIN!!!
#1
P0420 Code AGAIN!!!
Okay, this is my least favorite number. This is my third time recieving this code within 9 months. The first time I replaced the o2 sensor before the monifold. I then got the same error three months after and replaced my other oxygen sensor along with the previous one. Therefore I have had two new o2 sensors in my car for the last 3 months. They are the bosch universal ones. I read after installing that those aren't the best to get, but they are the cheapest. Anyway, I am now wondering if my cat is bad and what I should do about these stinkin o2 sensors. Please help me fix this problem so it won't come back again.
Thanks, Andrew
Thanks, Andrew
#3
Its a V6
The code states that "Catalyst System Efficiency Below Threshold", I was told this was a problem with the o2 sensors from reading other forums. Problem seemed to go away after I replaced the sensors but then came right back months later. What should I do??
Oh yeah, its also automatic. Same year as yours too (1998). Do I need to replace the cat converter? Tranny is also starting to slip a bit, errrr
Oh yeah, its also automatic. Same year as yours too (1998). Do I need to replace the cat converter? Tranny is also starting to slip a bit, errrr
#4
lots and lots of fail
Join Date: Dec 1999
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Originally Posted by Vladi17
The code states that "Catalyst System Efficiency Below Threshold", I was told this was a problem with the o2 sensors from reading other forums. Problem seemed to go away after I replaced the sensors but then came right back months later. What should I do??
Oh yeah, its also automatic. Same year as yours too (1998)
Oh yeah, its also automatic. Same year as yours too (1998)
DTC P0420: Catalyst System Efficiency Below Threshold
1) Reset the ECM/PCM.
2) Start the engine. Hold the engine at 3,000 rpm with no load (in Park or neutral) until the radiator fan comes on.
3) Except F23A4 SULEV engine: Test-drive at 40 - 55 mph (64 - 88 km/h) for approx. 2 minutes . Then decelerate for at least 3 seconds with the throttle completely closed. Then reduce the vehicle speed to 35 mph (56 km/h ), and try to hold it until the scan tool indicates FAIL or PASS as the TWC test result. F23A4 SULEV engine: Test-drive at 50 - 55 mph (80 - 88 km/h) for approx. 2 minutes . Then decelerate for at least 4 seconds with the throttle completely closed. Then accelerate to 55 mph (88 km/h ), and try to hold it until the scan tool indicates FAIL or PASS as the TWC test result. Is the test result FAIL? YES - Check the three way catalytic converter (TWC). If necessary, replace the TWC. NO - Intermittent failure, system is OK at this time.
So if P0420 comes on and it's the only code, either replace the TWC or have your Honda dealer (or someone else) test the TWC to see if it's bad or not. If there are multiple DTCs, troubleshoot those first. I only have P0420 I'll copy this in the DTC thread.
#5
Twc??
Sorry, I'm a little confused by your reply. Not sure what the Three-Way Converter (TWC) is. Also not sure what F23A4 means, could you please go a little bit more into details about what all this means. Also, I don't have a scan tool, I went to autozone for the reading. Should I buy one and have it plugged in while I drive?? I'm a little confused. Thanks for your quick response and all your help.
#8
lots and lots of fail
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Originally Posted by Vladi17
Sorry, I'm a little confused by your reply. Not sure what the Three-Way Converter (TWC) is. Also not sure what F23A4 means, could you please go a little bit more into details about what all this means. Also, I don't have a scan tool, I went to autozone for the reading. Should I buy one and have it plugged in while I drive?? I'm a little confused. Thanks for your quick response and all your help.
The scan tool referred to is a Honda tool that allows them to scan your entire ECU and get all sorts of data. I believe you can purchase one but they're very expensive.
#9
Thanks for the help
Okay, I think I'm gonna replace the cat converter, seems to me that has to be the problem since I replaced the both 02 sensors. Found one for around $140 (3.0 V6 Direct-Fit), if you know of cheaper please let me know.
#10
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Originally Posted by Vladi17
Okay, I think I'm gonna replace the cat converter, seems to me that has to be the problem since I replaced the both 02 sensors. Found one for around $140 (3.0 V6 Direct-Fit), if you know of cheaper please let me know.