P0420 - The issue is back and seems to be here to stay?

[TheRock0720]

Alright...so its the time of year again where I need to get my cars inspected, and once again my eclipse is giving me some issues.

Same thing happened last year, I was getting this code (P0420 - Catalyst System Efficiency Below Threshold). At one point I ended up getting the code P0140 - 02 Sensor Circuit No Activity Detected (Bank 1 Sensor 2), so we replaced that O2 Sensor and that code hasn't came back since. We managed to get the car inspected after weeks of trying. But not even after I left the parking lot of the inspection garage, my CEL came on once again for the P0420 code and its been on ever since (that was January/February of 2011).

We replaced the following (these are things that might be related to this issue):
Walker OEM Cat
Rear O2 Sensor
Spark Plugs, Wires, and Coil Pack

I looked under the car and there seems to be no leaks what so ever, very quiet. This car is bone stock and I plan to keep it this way, so no mods or anything like that has been done. I also should point out that I don't have much miles on this car, there is only 84,000 miles.

I could go out and buy a front O2 sensor and pray it fixes the issue, but before I jump the gun I was wondering if anyone else had this issue or has this issue? And what was the fix for you?

-TheRock0720

 

[CODE4]

Alright...so its the time of year again where I need to get my cars inspected, and once again my eclipse is giving me some issues.

Same thing happened last year, I was getting this code (P0420 - Catalyst System Efficiency Below Threshold). At one point I ended up getting the code P0140 - 02 Sensor Circuit No Activity Detected (Bank 1 Sensor 2), so we replaced that O2 Sensor and that code hasn't came back since. We managed to get the car inspected after weeks of trying. But not even after I left the parking lot of the inspection garage, my CEL came on once again for the P0420 code and its been on ever since (that was January/February of 2011).

We replaced the following (these are things that might be related to this issue):
Walker OEM Cat
Rear O2 Sensor
Spark Plugs, Wires, and Coil Pack

I looked under the car and there seems to be no leaks what so ever, very quiet. This car is bone stock and I plan to keep it this way, so no mods or anything like that has been done. I also should point out that I don't have much miles on this car, there is only 84,000 miles.

I could go out and buy a front O2 sensor and pray it fixes the issue, but before I jump the gun I was wondering if anyone else had this issue or has this issue? And what was the fix for you?

-TheRock0720

I am sure you have looked it up, but for the sake of mentioning here, the P0420 code rears its ugly head when the waveforms of the front O2 and rear O2 sensors closely match, indicating that the catalytic converter is performing poorly. Since your catalytic converter was replaced recently - the next culprits could be the sensors or a possible exhaust leak.

Before replacing sensors, it may be worth it to install a work-around such as below:

Vibrant Performance ::.

Intelligent Oxygen Sensor Simulator - SymTech Laboratories

 

[TheRock0720]

I am sure you have looked it up, but for the sake of mentioning here, the P0420 code rears its ugly head when the waveforms of the front O2 and rear O2 sensors closely match, indicating that the catalytic converter is performing poorly. Since your catalytic converter was replaced recently - the next culprits could be the sensors or a possible exhaust leak.

Before replacing sensors, it may be worth it to install a work-around such as below:

Vibrant Performance ::.

Intelligent Oxygen Sensor Simulator - SymTech Laboratories

I have been debating something similar to what you have showed me (those simulators/spacers). I might see if I can read both the 02 sensors and see how they're performing. Anyone know the specs off hand? If not, I'll read up on it.

I'll also check for leaks at the manifold and write back..

Thanks.

 

[eatsleepboostin]

Code No. P0420 Catalyst System Efficiency Below Threshold
(Bank 1) <2.0L Engine (Turbo), 2.4L Engine - Federal> Probable cause
[Comment]
Background
&#8226;The signal from the heated oxygen sensor which follows the catalytic converter differs
from that which precedes the catalytic converter. That is because the catalytic converter
purifies exhaust gas. When the catalytic converter has deteriorated, the signal from the
heated oxygen sensor which follows the catalytic converter becomes similar to that which
precedes the catalytic converter.
&#8226;The engine control module checks the output of the heated oxygen sensor signals.
Check Area
&#8226;Engine speed is not less than 2,500 <2.0L Engine (Turbo)> or 2,600 <2.4L Engine> r/min.
&#8226;Volume air flow sensor output frequency is between 44 and 240 Hz <M/T> or 50 and
240 Hz <A/T>. <2.0L Engine (Turbo)>
&#8226;Intake air temperature is -10&#176;C (14&#176;F) or higher
&#8226;Barometric pressure is 76 kPa (11 psi.) or higher.
&#8226;Closed throttle position switch: OFF
&#8226;Under the closed loop air-fuel ratio control.
&#8226;Monitoring Time: 140 sec
Judgement Criteria
&#8226;Oxygen sensor (rear) signal and oxygen sensor (front) signal are abnormal. &#8226;Catalytic converter deteriorated
&#8226;Heated oxygen sensor failed
&#8226;Engine control module failed



Code No. P0136 O2 (Heated Oxygen) Sensor Circuit
Malfunction (Bank 1 Sensor 2) Probable cause
[Comment]
Background
&#8226;The engine control module checks for an open circuit in the heated oxygen sensor output
line.
Check Area
&#8226;Coolant temperature sensor: normal
&#8226;Heated oxygen sensor signal voltage has continued to be 0.1 V or lower for 3 min or
more after the starting sequence was completed.
&#8226;Engine coolant temperature is not lower than 80&#176;C (176&#176;F)
&#8226;Engine speed is higher than 1200 r/min.
&#8226;Volumetric efficiency is not lower than 25%.
&#8226;Intake air temperature is -10&#176;C (14&#176;F) or higher
&#8226;Barometric pressure is 76 kPa (11 psi.) or higher.
&#8226;Monitoring Time: 7 - 10 sec
Judgement Criteria
&#8226;Input voltage supplied to the engine control module interface circuit is not lower than 4.5
V when 5 V is applied to the heated oxygen sensor output line via a resistor.
&#8226;Making the air-fuel ratio 15% richer doesn't result in raising the heated oxygen sensor
output voltage beyond 0.1 V. &#8226;Heated oxygen sensor failed
&#8226;Open circuit in heated oxygen sensor output
line
&#8226;Engine control module failed




Code No. P0130 O2 (Heated Oxygen) Sensor Circuit
Malfunction (Bank 1 Sensor 1) Probable cause
[Comment]
Background
&#8226;When the heated oxygen sensor begins to deteriorate, the oxygen sensor signal response
becomes poor.
&#8226;The engine control module forcibly varies the air/fuel mixture to make it leaner and richer,
and checks the response speed of the heated oxygen sensor.
In addition, the engine control module also checks for an open circuit in the heated oxygen
sensor output line.
Check Area, Judgement Criteria
1.Check Area
&#8226;Engine coolant temperature sensor: normal
&#8226;Heated oxygen sensor signal voltage has continued to be 0.1 V or lower for 3 min
or more after the starting sequence was completed.
&#8226;Engine coolant temperature is higher than 80&#176;C (176&#176;F).
&#8226;Engine speed is higher than 1200 r/min.
&#8226;Volumetric efficiency is not lower than 25%.
&#8226;Intake air temperature is -10&#176;C (14&#176;F) or higher
&#8226;Barometric pressure is 76 kPa (11 psi.) or higher.
Judgement Criteria
&#8226;Input voltage supplied to the engine control module interface circuit is not lower than
4.5 V when 5 V is applied to the heated oxygen sensor output line via a resistor.
2.Check Area
&#8226;Engine coolant temperature sensor: Normal
&#8226;Engine coolant temperature is not lower than 50&#176;C (122&#176;F).
&#8226;Engine speed is between 1500 and 3000 r/min. <M/T>
&#8226;Engine speed is between 1100 and 3000 r/min. <A/T>
&#8226;Volumetric efficiency is 25 - 60%.
&#8226;Intake air temperature is -10&#176;C (14&#176;F) or higher
&#8226;Barometric pressure is 76 kPa (11 psi.) or higher.
&#8226;Under the closed loop air-fuel control.
&#8226;Monitoring time: 8 sec
Judgement Criteria
&#8226;When the air-fuel ratio is forcibly changed (lean to rich and rich to lean), the heated
oxygen sensor signal doesn't provide response within 1.2 sec.
&#8226;Monitored only once per trip. &#8226;Heated oxygen sensor deteriorated
&#8226;Open circuit in heated oxygen sensor output
line
&#8226;Engine control module failed

 

[TheRock0720]

No leaks anywhere in the exhaust system, solid as a rock!

Going to get a "spacer" for the rear O2 Sensor and see how that goes. Have heard it works, and its only a few dollars so it's not a bad place to start.

This is where I was referred:
ScoobyMods - View Single Post - Rear O2 Sensor fix for CEL code P0420

UPDATE- "Spacers" are installed, vehicle OBD system is almost ready for "testing", will keep this post updated.

 

[Janaelen]

Any updates?

 

[TheRock0720]

yes, check engine light is still out. passed state emissions. all is well.

 

[bullettdsm]

yes, check engine light is still out. passed state emissions. all is well.

Ah the feeling of triumph! Congrats.

MB

 

[TheRock0720]

Ah the feeling of triumph! Congrats.

MB

haha yes yes, thank you.

 

[Janaelen]

Thanks for the update and Congrats! I'll be sure to to archive this as a possible fix the next time I cross this issue.