Could putting the complete stock exhaust back on possibly resolve this?
P0420 Cat warmup temp below efficiency.
Hi guys. Looking for some advise on this. A few weeks ago I got the code P0420. It comes on and off sporadically, but when its on the engine will sometimes cut out. This only happeneds while driving, more specifically, while slowing down to a stop light. I can start it up again and its fine, no rough idle etc. The only mods I have are a injen sri and an eBay cat back.
Last year, however, I had to but the stock muffler on the cat back as the eBay muffler was corroding inside out.
I'm wondering if anyone can help me pinpoint the problem. My car is a 2006 GT
Last year, however, I had to but the stock muffler on the cat back as the eBay muffler was corroding inside out.
I'm wondering if anyone can help me pinpoint the problem. My car is a 2006 GT
1 - 11 of 11 Posts
Could very well be that your cats are clogged, I believe the '06s and early production '07s had this issue crop up fairly often.
Doesn't sound like your mods have anything to do with your code.
Doesn't sound like your mods have anything to do with your code.
Are you sure it's a P0420 code?? Can't find that code in the Service Manual.
P0421 Warm up catalyst efficiency below threshold (bank 1, rear CAT) Page 13B-652
http://tearstone.com/eclipsefsm/2006_PS24S_MMNA_SM_PDF/GR00005900A-13B.pdf
^^ This book has a broken link, so you cannot get to page 13B-652^^
But Martino is correct, this code has nothing to do with your mods. This has to do with the rear CAT, Right Bank, and/or Bank #1. LOL!! You'll hear these types references when talking about the rear CAT next to the firewall. This is also true when you start messing with the O2 sensors.
Back in 2006 there was a TSB (Technical Service Bulletin) for the rear CAT's going bad and at any Mitsu Service at the dealership they were suppose to re-flash the computer to prevent this from happening.
Let me look-up some further information on this code~~
P0421 Warm up catalyst efficiency below threshold (bank 1, rear CAT) Page 13B-652
http://tearstone.com/eclipsefsm/2006_PS24S_MMNA_SM_PDF/GR00005900A-13B.pdf
^^ This book has a broken link, so you cannot get to page 13B-652^^
But Martino is correct, this code has nothing to do with your mods. This has to do with the rear CAT, Right Bank, and/or Bank #1. LOL!! You'll hear these types references when talking about the rear CAT next to the firewall. This is also true when you start messing with the O2 sensors.
Back in 2006 there was a TSB (Technical Service Bulletin) for the rear CAT's going bad and at any Mitsu Service at the dealership they were suppose to re-flash the computer to prevent this from happening.
Let me look-up some further information on this code~~
TECHNICAL DESCRIPTION
•The signal from the rear heated oxygen sensor differs from the front heated oxygen sensor, because the catalytic converter purifies exhaust gas. When the catalytic converter has deteriorated, the signal from the front heated oxygen sensor becomes similar to the rear heated oxygen sensor.
•The ECM <M/T> or the PCM <A/T> compares the output of the front and rear heated oxygen sensor signals.
.
DESCRIPTIONS OF MONITOR METHODS
Front and rear heated oxygen sensor rich/lean switching frequencies are nearly equal.
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
•Heated oxygen sensor (front) monitor
•Heated oxygen sensor (rear) monitor
•Heated oxygen sensor heater (front) monitor
•Heated oxygen sensor heater (rear) monitor
•Misfire monitor
•Fuel system monitor
•Air/fuel ratio feedback monitor
Sensor (The sensor below is determined to be normal)
•Mass airflow sensor
•Engine coolant temperature sensor
•Intake air temperature sensor
•Barometric pressure sensor
•Throttle position sensor
•Accelerator pedal position sensor
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are: )
•Right bank side catalytic converter deteriorated.
•Right bank heated oxygen sensor failed.
•Exhaust leak.
•ECM failed. <M/T>
•PCM failed. <A/T>
•The signal from the rear heated oxygen sensor differs from the front heated oxygen sensor, because the catalytic converter purifies exhaust gas. When the catalytic converter has deteriorated, the signal from the front heated oxygen sensor becomes similar to the rear heated oxygen sensor.
•The ECM <M/T> or the PCM <A/T> compares the output of the front and rear heated oxygen sensor signals.
.
DESCRIPTIONS OF MONITOR METHODS
Front and rear heated oxygen sensor rich/lean switching frequencies are nearly equal.
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
•Heated oxygen sensor (front) monitor
•Heated oxygen sensor (rear) monitor
•Heated oxygen sensor heater (front) monitor
•Heated oxygen sensor heater (rear) monitor
•Misfire monitor
•Fuel system monitor
•Air/fuel ratio feedback monitor
Sensor (The sensor below is determined to be normal)
•Mass airflow sensor
•Engine coolant temperature sensor
•Intake air temperature sensor
•Barometric pressure sensor
•Throttle position sensor
•Accelerator pedal position sensor
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are: )
•Right bank side catalytic converter deteriorated.
•Right bank heated oxygen sensor failed.
•Exhaust leak.
•ECM failed. <M/T>
•PCM failed. <A/T>
Trouble shooting~~~ Do you know how to use a Multi-Meter??
Depending how old the O2 sensors are on this cat, you might have some fun removing these O2 sensors. You will need penetrating oil, an O2 sensor socket wrench to remove the sensors and check continuity of the sensors. Either way around... you will most likely end-up replacing both the upper and lower O2 sensors. Bosch O2 Sensors cost around $80 each, give or take $10.00.
If you didn't stripe the threads on the cat go ahead and install the new O2 sensors, mind do not put the wrong sensors in the wrong holes, you need an up-stream sensor, and a down stream sensor. Remove the set code and take it for a test drive, if the code comes back... you have a bad cat.
You didn't waste your money when you bought those sensors. When you install a new cat, you should install new O2 sensors also!! The cat will cost around $700.00. If you do the job yourself, you better have a good tool chest. Labor for this job can cost between $400 to $700.
If you do require further information concerning removal of O2 sensors, removal and installation of the cat, just ask, we do have an Eclipse Factory Service Manual Link. You should bookmark this link, it will become your best friend... http://tearstone.com/2006-eclipse-factory-service-manual/ This is a very large service manual that contains 47 books, so if you need help finding something, just ask.
Depending how old the O2 sensors are on this cat, you might have some fun removing these O2 sensors. You will need penetrating oil, an O2 sensor socket wrench to remove the sensors and check continuity of the sensors. Either way around... you will most likely end-up replacing both the upper and lower O2 sensors. Bosch O2 Sensors cost around $80 each, give or take $10.00.
If you didn't stripe the threads on the cat go ahead and install the new O2 sensors, mind do not put the wrong sensors in the wrong holes, you need an up-stream sensor, and a down stream sensor. Remove the set code and take it for a test drive, if the code comes back... you have a bad cat.
You didn't waste your money when you bought those sensors. When you install a new cat, you should install new O2 sensors also!! The cat will cost around $700.00. If you do the job yourself, you better have a good tool chest. Labor for this job can cost between $400 to $700.
If you do require further information concerning removal of O2 sensors, removal and installation of the cat, just ask, we do have an Eclipse Factory Service Manual Link. You should bookmark this link, it will become your best friend... http://tearstone.com/2006-eclipse-factory-service-manual/ This is a very large service manual that contains 47 books, so if you need help finding something, just ask.
$700 for a new cat? If that's the way it goes, it's a perfect opportunity for you to go aftermarket with some quality headers and a DP. A torn flexpipe in my old car was what got me to shell out close to $1200 for a complete header-back and wideband lol. I had no regrets, and if I were in your shoes, I'd do the same again.
Very true Martino, and I never regretted installing my headers and exhaust system install either, love the wild horses at WOT!!
I'd hate to here what a CAT costs in the Great White North....
I'd hate to here what a CAT costs in the Great White North....
I just changed both my O2 sensors after getting the P0421 code. After test drive no code came back. Should the code come back on instantly if it is the cat?
I just changed both my O2 sensors after getting the P0421 code. After test drive no code came back. Should the code come back on instantly if it is the cat?
Welcome to the club! = D
no, it wont come on right away... the system needs to do a cycle check... roughly 50-100 miles or so...now that you have the codes cleared, it will cycle through its checks and then you may or may not see the light again, depending on if that fixed your problem or not. Hopefully you dont see it again. : )
OP, do what clovis is saying.... or if you know someone who has a spare O2 sensor you can borrow from a 4g, try another O2 sensor...( its cheaper then an exaust) I'll look to see if I still have one... but clovis is right, there going to be a pain to get out.... deff spray them with WD-40 or something and let it sit/soak in before trying to turn them.
like plain jane said, it was an issue with 06-07.... I think with GT's...
I think it was usually the rears too.... the one clovis is talking about...
Clovis do I replace the top and bottom on right side or just bottom?Trouble shooting~~~ Do you know how to use a Multi-Meter??
Depending how old the O2 sensors are on this cat, you might have some fun removing these O2 sensors. You will need penetrating oil, an O2 sensor socket wrench to remove the sensors and check continuity of the sensors. Either way around... you will most likely end-up replacing both the upper and lower O2 sensors. Bosch O2 Sensors cost around $80 each, give or take $10.00.
If you didn't stripe the threads on the cat go ahead and install the new O2 sensors, mind do not put the wrong sensors in the wrong holes, you need an up-stream sensor, and a down stream sensor. Remove the set code and take it for a test drive, if the code comes back... you have a bad cat.
You didn't waste your money when you bought those sensors. When you install a new cat, you should install new O2 sensors also!! The cat will cost around $700.00. If you do the job yourself, you better have a good tool chest. Labor for this job can cost between $400 to $700.
If you do require further information concerning removal of O2 sensors, removal and installation of the cat, just ask, we do have an Eclipse Factory Service Manual Link. You should bookmark this link, it will become your best friend... 2006 Eclipse Factory Service Manual – Tearstone This is a very large service manual that contains 47 books, so if you need help finding something, just ask.
1 - 11 of 11 Posts
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