P0420 CEL Help
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Joined: Feb 2014
Posts: 92
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From: So Cal
P0420 CEL Help
I just installed a CAI Skunk2 header and cat back exhaust system. Drove the car for about 2 days and now the "check emission system" light came on. The message screen reads P0420 code.
My car only has 1400 miles so I don't think my O2 sensor is bad.
Any suggestions?
Thanks
My car only has 1400 miles so I don't think my O2 sensor is bad.
Any suggestions?
Thanks
so the skunk pipe has 2 defoulers.
check them both. perhaps loose. perhaps wire melted from o2.
one you can almost see from the top behind the motor.
the other would be near the other end of the pipe....down where it meets the cat back.
that skunk pipe is rather new so .......
check them both. perhaps loose. perhaps wire melted from o2.
one you can almost see from the top behind the motor.
the other would be near the other end of the pipe....down where it meets the cat back.
that skunk pipe is rather new so .......
Burning Brakes
Joined: Feb 2011
Posts: 972
Likes: 241
From: STL
Mine threw a CEL with the rv6 pipe if I opened it up all the time without letting the motor warm up.
If you live in a very urban area, and don't drive your car very far, it seems pretty reasonable that the downpipe and the fact that the o2 sensors aren't getting into a "ready" state could be the issue. If you have the throttle open, then let it snap shut, without the motor and sensors warmed up, this is most likely the culprit.
I documented my trials and tribulations with that earlier when I was going to get emissions tested.
Your best bet is to get a flashpro and disable the o2, only enable them and drive the car so they go ready when time for emissions testing.
If you live in a very urban area, and don't drive your car very far, it seems pretty reasonable that the downpipe and the fact that the o2 sensors aren't getting into a "ready" state could be the issue. If you have the throttle open, then let it snap shut, without the motor and sensors warmed up, this is most likely the culprit.
I documented my trials and tribulations with that earlier when I was going to get emissions tested.
Your best bet is to get a flashpro and disable the o2, only enable them and drive the car so they go ready when time for emissions testing.
Thread Starter
Advanced
Joined: Feb 2014
Posts: 92
Likes: 19
From: So Cal
Mine threw a CEL with the rv6 pipe if I opened it up all the time without letting the motor warm up.
If you live in a very urban area, and don't drive your car very far, it seems pretty reasonable that the downpipe and the fact that the o2 sensors aren't getting into a "ready" state could be the issue. If you have the throttle open, then let it snap shut, without the motor and sensors warmed up, this is most likely the culprit.
I documented my trials and tribulations with that earlier when I was going to get emissions tested.
Your best bet is to get a flashpro and disable the o2, only enable them and drive the car so they go ready when time for emissions testing.
If you live in a very urban area, and don't drive your car very far, it seems pretty reasonable that the downpipe and the fact that the o2 sensors aren't getting into a "ready" state could be the issue. If you have the throttle open, then let it snap shut, without the motor and sensors warmed up, this is most likely the culprit.
I documented my trials and tribulations with that earlier when I was going to get emissions tested.
Your best bet is to get a flashpro and disable the o2, only enable them and drive the car so they go ready when time for emissions testing.
there is no flashpro for his 13 wagon/ YET
i have the OBDII dongle and that app TORQUE.
I can clear all my codes that way.
And if you have tech there is a way to clear the code out the nav too.
do a quick search. you hold like 3 or 4 buttons down ar once
and you get into the nav to clear them.
I Forgot; i had the same issue twice when my car is not full warm and I hit it accelerating and have to let off quick.
only 2 times my rv6 thru a code.
maybe its the same
i have the OBDII dongle and that app TORQUE.
I can clear all my codes that way.
And if you have tech there is a way to clear the code out the nav too.
do a quick search. you hold like 3 or 4 buttons down ar once
and you get into the nav to clear them.
I Forgot; i had the same issue twice when my car is not full warm and I hit it accelerating and have to let off quick.
only 2 times my rv6 thru a code.
maybe its the same
Last edited by robpp; Mar 11, 2014 at 06:52 PM.
Pro
Joined: Jul 2012
Posts: 674
Likes: 235
From: Orlando
I always let my car warm up to operating temp b4 punching it due to hearing about this problem from all the guys w the rv-6 pipe.. I have yet to throw a code once and it's been on the car for more than three weeks. The skunk2 pipe should have come with only one defouler and that is solely for the secondary o2 sensor, the one that is placed after the first cat on the factory pipe.
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Burning Brakes
Joined: Aug 2006
Posts: 865
Likes: 118
From: West Burbs, Chicago
The CEL the RV6 PCD guys get is P0139, not sure what causes the P0420 CEL...maybe the opposite and its seeing too little oxygen in the exhaust?
P0139 code is for faulty O2 sensor, exhaust leak, or damaged O2 wiring.
When your engine is cold, the air going through the engine is cooler and more dense. The denser the air, the more O2 there is in the air. The ECU calculates how much fuel is required to prevent the engine from going too lean. When you get on the gas when the engine is cold, the exhaust slightly has more O2 in it which triggers the P0139 code, sensing too much O2 in the exhaust. Maybe a slightly longer or shorter defouler or maybe drilling out the defouler opening bigger would help, but its a really fine line tuning the defouler to trick the O2 sensor to think everything is normal.
You can still get on the gas when the engine is cold, but you might trigger the CEL. All you need to do is just clear the code using an OBD reader.
When your engine is cold, the air going through the engine is cooler and more dense. The denser the air, the more O2 there is in the air. The ECU calculates how much fuel is required to prevent the engine from going too lean. When you get on the gas when the engine is cold, the exhaust slightly has more O2 in it which triggers the P0139 code, sensing too much O2 in the exhaust. Maybe a slightly longer or shorter defouler or maybe drilling out the defouler opening bigger would help, but its a really fine line tuning the defouler to trick the O2 sensor to think everything is normal.
You can still get on the gas when the engine is cold, but you might trigger the CEL. All you need to do is just clear the code using an OBD reader.
Burning Brakes
Joined: Aug 2006
Posts: 865
Likes: 118
From: West Burbs, Chicago
The code reads:
Catalyst System Efficiency Below Threshold (Bank 1)
Possible Causes:
Leaded fuel was used where unleaded was called for
A damaged or failed oxygen sensor (HO2S)
Downstream oxygen sensor (HO2S) wiring damaged or connected improperly
The engine coolant temperature sensor is not working properly
Damaged or leaking exhaust manifold / catalytic converter / muffler / exhaust pipe
Retarded spark timing
The oxygen sensors in front and behind the converter are reporting too similar of readings
Leaking fuel injector or high fuel pressure
Cylinder misfire Oil contamination
CEL is probably due to the cause I highlighted since the Skunk2 pipe eliminates both cats.
Catalyst System Efficiency Below Threshold (Bank 1)
Possible Causes:
Leaded fuel was used where unleaded was called for
A damaged or failed oxygen sensor (HO2S)
Downstream oxygen sensor (HO2S) wiring damaged or connected improperly
The engine coolant temperature sensor is not working properly
Damaged or leaking exhaust manifold / catalytic converter / muffler / exhaust pipe
Retarded spark timing
The oxygen sensors in front and behind the converter are reporting too similar of readings
Leaking fuel injector or high fuel pressure
Cylinder misfire Oil contamination
CEL is probably due to the cause I highlighted since the Skunk2 pipe eliminates both cats.
Last edited by thunderbt3; Mar 12, 2014 at 11:45 AM.
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