P0138 Error Code - Post Cat O2 Sensor
10-12-2004, 08:15 AM
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P0138 Error Code - Post Cat O2 Sensor
I've installed a high-flow cat converter on my '99 Integra and after installing a O2 simulator to take care of the check-engine light on my dash, i keep getting a high-volts error code (O2 Sensor High-Volts - bank 1 sensor 2).
i tried all kinds of things with this O2 simulator - adjusting the High Volts, the Low Volts and the Frequency of the signal.
Does anyone know how to get rid of that "check engine light" once a high-flow is installed on an Integra?
any details on previous experiences would be helpful.
thanks much!
i tried all kinds of things with this O2 simulator - adjusting the High Volts, the Low Volts and the Frequency of the signal.
Does anyone know how to get rid of that "check engine light" once a high-flow is installed on an Integra?
any details on previous experiences would be helpful.
thanks much!
10-12-2004, 08:42 AM
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Re: P0138 Error Code - Post Cat O2 Sensor (stefanne3)
so after clearing the code, it comes back? i would just try hooking the stock o2 senor back up, clear the code, then run the car with the secondary o2 out of the exhaust stream.
10-12-2004, 09:03 AM
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Re: P0138 Error Code - Post Cat O2 Sensor (sleepyEK)
it comes back? like you wouldn't belive :-D I've been struggling with this for over 6 months.
The 1st O2 sensor (pre-cat) has not been touched - i think that's needed for the engine to run.
The post cat i did everything with it. I took it out, plugged the hole with a special cat bolt. No go - it gives me some type of ... low volts error code and a cat converter malfunction.
It has a heater inside it and that warms up as the engine is cold - that's to speed up the reading of the gases in the exhaust (so it doesn't wait for the exhaust to heat up the sensor.
to answer your question - if i take the post-cat sensor out completely but left connected, besides the fact that it's as loud as a tractor trailer, it still send the error code.
It's almost as if this thing's alive and it knows what i'm doing to it.
Someone out there had to have had this problem before. I refuse to belive i'm the first one to replace the cat converter on an Integra!
The 1st O2 sensor (pre-cat) has not been touched - i think that's needed for the engine to run.
The post cat i did everything with it. I took it out, plugged the hole with a special cat bolt. No go - it gives me some type of ... low volts error code and a cat converter malfunction.
It has a heater inside it and that warms up as the engine is cold - that's to speed up the reading of the gases in the exhaust (so it doesn't wait for the exhaust to heat up the sensor.
to answer your question - if i take the post-cat sensor out completely but left connected, besides the fact that it's as loud as a tractor trailer, it still send the error code.
It's almost as if this thing's alive and it knows what i'm doing to it.
Someone out there had to have had this problem before. I refuse to belive i'm the first one to replace the cat converter on an Integra!
10-12-2004, 10:49 AM
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Re: P0138 Error Code - Post Cat O2 Sensor (stefanne3)
that's funny, i've always been able to just take out the secondary. right now i'm not using it. i have a straight through exhaust now. and by the way are you sure you don't have the o2 sensors swapped, many a time people have come to me with this problem and their sensors are swapped.
the secondary is just to signal cat failure. so definitely leave it out.
the secondary is just to signal cat failure. so definitely leave it out.
10-12-2004, 12:01 PM
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Re: P0138 Error Code - Post Cat O2 Sensor (sleepyEK)
yes - i'm sure it's the sensor after the cat converter.
First, i think if it weren't my engine wouldn't run .. because the first one is used to adjust the fuel/air mixture based on the richness of the exhaust.
Second - my mechanic told me that there's really only one way to connect these two sensors - one in the front and one in the back. the one in the front wouldn't even have a long enough wire to go to the back.
now - what kind of car do you have? It's a honda, isn't it? Usually i'm not surprised if these imports have a lot of stuff running on electronics. It's not very surprising for this to be this stubborn, but it is annoying - i'll give you that.
When you said you took the sensor out, did you mean you cut it from the wiring, so you just had some wires sticking out? Or did you just unscrew it and tied it to the bottom of the car.
What i did is i unscrewed it and tied to the bottom of the car with a zip tie. I also put some type of plastic sponge on it so that junk wouldn't get in there if i drive it like that. The heater inside the sensor (that i had no idea about) started heating up, and melting the sponge i had on there. I only knew about this when i realized if i take it out, i'll still get the light on my dash.
This was after weeks of searching for a plug ... so that i wouldn't drive with the hole opened - it would've been unbearably loud.
After all this i started looking into getting a simulator installed on there - that taps into the wires of this sensor and sends the appropriate signal to the computer. That's where i am right now.
i have not cut the wires to the post-cat sensor - the sensor is still screwed in and i'm only trying to adjust the simulator signal to match what the computer is expecting from the O2 sensor.
let me know if this helps ... i'm definitely interested in how you got it not to error out anymore.
thanks buddy!
First, i think if it weren't my engine wouldn't run .. because the first one is used to adjust the fuel/air mixture based on the richness of the exhaust.
Second - my mechanic told me that there's really only one way to connect these two sensors - one in the front and one in the back. the one in the front wouldn't even have a long enough wire to go to the back.
now - what kind of car do you have? It's a honda, isn't it? Usually i'm not surprised if these imports have a lot of stuff running on electronics. It's not very surprising for this to be this stubborn, but it is annoying - i'll give you that.
When you said you took the sensor out, did you mean you cut it from the wiring, so you just had some wires sticking out? Or did you just unscrew it and tied it to the bottom of the car.
What i did is i unscrewed it and tied to the bottom of the car with a zip tie. I also put some type of plastic sponge on it so that junk wouldn't get in there if i drive it like that. The heater inside the sensor (that i had no idea about) started heating up, and melting the sponge i had on there. I only knew about this when i realized if i take it out, i'll still get the light on my dash.
This was after weeks of searching for a plug ... so that i wouldn't drive with the hole opened - it would've been unbearably loud.
After all this i started looking into getting a simulator installed on there - that taps into the wires of this sensor and sends the appropriate signal to the computer. That's where i am right now.
i have not cut the wires to the post-cat sensor - the sensor is still screwed in and i'm only trying to adjust the simulator signal to match what the computer is expecting from the O2 sensor.
let me know if this helps ... i'm definitely interested in how you got it not to error out anymore.
thanks buddy!
10-12-2004, 06:43 PM
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Re: P0138 Error Code - Post Cat O2 Sensor (stefanne3)
my car is a '97 dx hatch. the exhaust i built doesn't use a cat, and i figured the ecu wouldn't like it if i just put the secondary in the unrefined exhaust stream. so i just tied it up in the engine bay. nothing seems to be getting on the sensor. and i'm not posting any codes. also the mixture is enrichened slightly, but nothing that won't be to my advantage when i put the other engine mods on. i can't figure out why your car is being stubborn. in all my experience, i have never seen an obd2 throw a code for not having the secondary in the exhaust. i'll keep trying to figure it out though. sorry
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10-13-2004, 08:32 AM
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Re: (PrettyLude)
that's what i did .. i wired the simulator to the wires coming from the post o2 sensor.
However - because of the special signal the ECU is expecting, i keep getting a P0138 High Volts error code on my dash.
I even tried using an adjustable simulator (adjusting the high-volts, low-volts and frequency). I can have this simulator send signals anywhere between 0-0.4V for the low range and 0.5-1V on the high-range (probably even more adjustable). The frequency anywhere from 1 sec to 9 secs.
Nothing seems to get rid of this High-Volts error code ...
However - because of the special signal the ECU is expecting, i keep getting a P0138 High Volts error code on my dash.
I even tried using an adjustable simulator (adjusting the high-volts, low-volts and frequency). I can have this simulator send signals anywhere between 0-0.4V for the low range and 0.5-1V on the high-range (probably even more adjustable). The frequency anywhere from 1 sec to 9 secs.
Nothing seems to get rid of this High-Volts error code ...
10-13-2004, 01:03 PM
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Re: (PrettyLude)
what do you mean wire it at the ECU? I think the instructions that came with the simulator said that i should cut the wire going to the simulator. That's what i did - i found the place that the wires go inside the car from the sensor and i spliced those connecting the wires from the simulator with those of the sensor.
There are not exactly at the ECU itself - but under the dash. However i don't think these sensor wires are connected to anything else on the way before they go into the ECU. So i wouldn't think it would make a difference where i cut them, right?
There are not exactly at the ECU itself - but under the dash. However i don't think these sensor wires are connected to anything else on the way before they go into the ECU. So i wouldn't think it would make a difference where i cut them, right?
10-14-2004, 03:43 AM
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Re: (stefanne3)
So you have your o2 sensor out of your cat(actually no cat at all), and you also have an OBD2 simulator??
Why not just cut the 02 sim out, and leave the second o2 sensor reading that engine bay air?? You will eliminate that O2 simulator completely as a factor.
Why not just cut the 02 sim out, and leave the second o2 sensor reading that engine bay air?? You will eliminate that O2 simulator completely as a factor.
10-14-2004, 04:25 AM
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Re: (civic-4-ges)
no - i don't have the o2 sensor out of my cat (actually it is a cat - it's a high flow cat).
I did have it outside of the exhaust stream, tied to a cable underneath the car, but it was giving me an error message (something about a catalytic converter malfunction). I don't really remember the error code - but i think it was either low volts or high volts. It somehow knew the air around it is too clean or something.
so i put it back and i tries using an O2 simulator. It's not an ODB2 simulator ... but if you're wondering - yes i do have an ODB2 code reader tool. That's how i'm reading all of these codes.
i think cutting the wires to the o2 sensor would also give me an error code ... it will not get the right signal from the sensor and will know it's no longer there. That's why i turned to O2 simulators to begin with.
I did have it outside of the exhaust stream, tied to a cable underneath the car, but it was giving me an error message (something about a catalytic converter malfunction). I don't really remember the error code - but i think it was either low volts or high volts. It somehow knew the air around it is too clean or something.
so i put it back and i tries using an O2 simulator. It's not an ODB2 simulator ... but if you're wondering - yes i do have an ODB2 code reader tool. That's how i'm reading all of these codes.
i think cutting the wires to the o2 sensor would also give me an error code ... it will not get the right signal from the sensor and will know it's no longer there. That's why i turned to O2 simulators to begin with.
10-14-2004, 04:35 AM
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Re: (stefanne3)
So you have a high flow cat, and the O2 sensor is in it??
Its expecting exhaust cleaned by the catalyst, not exhaust that is not. Of course its going to give you a high voltage.
High Flow Cat=Resonator generally speaking. Is there actually any catalyst material in it?
Its expecting exhaust cleaned by the catalyst, not exhaust that is not. Of course its going to give you a high voltage.
High Flow Cat=Resonator generally speaking. Is there actually any catalyst material in it?
10-14-2004, 06:48 AM
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Re: (civic-4-ges)
yes - a high flow cat and the engine post O2 sensor inside it (screwed in - the way the factory cat converter had a hole).
of course it's expecting cleaner exhaust and will give me a high-volts error code - that's precisely why i got the O2 simulator. To regulate/distort the signal coming from the O2 sensor based on what the ECU expects to see and thus eliminate the code.
i don't know if it's got any "material" in it. I do know it's a straight pipe with regular holes in it - like a strainer. The pipe is straight through, with holes on the side walls. I'm not sure how much of the exhaust still gets converted, but that's how it looks.
of course it's expecting cleaner exhaust and will give me a high-volts error code - that's precisely why i got the O2 simulator. To regulate/distort the signal coming from the O2 sensor based on what the ECU expects to see and thus eliminate the code.
i don't know if it's got any "material" in it. I do know it's a straight pipe with regular holes in it - like a strainer. The pipe is straight through, with holes on the side walls. I'm not sure how much of the exhaust still gets converted, but that's how it looks.
10-14-2004, 05:53 PM
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Re: (stefanne3)
I thought you just said you don't have an OBD2 sim???
IDK much about o2 sensor sim's themselves, my seconday sensor is under my passenger seat with my harness extension
IDK much about o2 sensor sim's themselves, my seconday sensor is under my passenger seat with my harness extension
10-15-2004, 01:45 PM
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Re: (civic-4-ges)
that chat dealsy wasn't really working ... i ended up waiting for a long time for messages to go through. - i think they need to improve on that technology.
don't worry about asking questions - it's kind of hard to come up with the right story over the internet.
I'm not sure what you call the ODB2 simulator. I have an ODB II code reader - that's the tool that i attach to the port on my car to read the codes.
The only simulator that i have is what they call an O2 Simualator - the oxygen simulator. At least that's what everyone seems to call it.
That i do have attached (the o2 simulator).
Did you just cut your secondary sensor out? it doesn't give you any error codes?
don't worry about asking questions - it's kind of hard to come up with the right story over the internet.
I'm not sure what you call the ODB2 simulator. I have an ODB II code reader - that's the tool that i attach to the port on my car to read the codes.
The only simulator that i have is what they call an O2 Simualator - the oxygen simulator. At least that's what everyone seems to call it.
That i do have attached (the o2 simulator).
Did you just cut your secondary sensor out? it doesn't give you any error codes?
10-16-2004, 04:32 AM
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Re: (stefanne3)
The O2 simulator would connect to your O2 sensor wires, and is definately not an OBD2 scanner. They send a pre-determined voltage to the ecu via the O2 sensor signal wire, which tells the ecu that the sensor ir reading clean.
Is this what you have??
Is this what you have??
10-17-2004, 09:24 AM
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man i just think he wired something up wrong, i had it wired up one time and it was giving the same problem, it appears mines i had to cut the ecu wire and butt connect it back together
10-17-2004, 10:17 AM
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Re: (stefanne3)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by stefanne3 »</TD></TR><TR><TD CLASS="quote">The pipe is straight through, with holes on the side walls. I'm not sure how much of the exhaust still gets converted, but that's how it looks.</TD></TR></TABLE>
You don't have a catalytic converter anymore, you have a resonator. Nothing gets converted into anything with that. It just takes the place of the cat. I really don't know why they are sold as a high flow cat when thats not what they are. I bought the same thing (ebay special) and thats what I got too. Don't matter much to me, I got OBD0.
You don't have a catalytic converter anymore, you have a resonator. Nothing gets converted into anything with that. It just takes the place of the cat. I really don't know why they are sold as a high flow cat when thats not what they are. I bought the same thing (ebay special) and thats what I got too. Don't matter much to me, I got OBD0.
10-18-2004, 07:51 AM
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Re: (drdisco69)
ODB 0, eh?
What i also don't get is why the ODB acronym is tied to this device, when i thought that the ODB 2 only refers to the device that plugs into the ODB 2 connector to read the codes in the computer.
odb 0 - as in odb nothing, right? (because of the smiley face)
What i also don't get is why the ODB acronym is tied to this device, when i thought that the ODB 2 only refers to the device that plugs into the ODB 2 connector to read the codes in the computer.
odb 0 - as in odb nothing, right? (because of the smiley face)
10-18-2004, 07:56 AM
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Re: (civic-4-ges)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by civic-4-ges »</TD></TR><TR><TD CLASS="quote">The O2 simulator would connect to your O2 sensor wires, and is definately not an OBD2 scanner. They send a pre-determined voltage to the ecu via the O2 sensor signal wire, which tells the ecu that the sensor ir reading clean.
Is this what you have??</TD></TR></TABLE>
yes - that's what i got. I wired the O2 simulator to the O2 sensor wires going inside the car from underneath.
I pushed a metal rod from underneath through the rubber gasket in the floor, and by pulling on wires, i figured out which ones are the sensor wires. I sliced those buggers and i connected the O2 simulator to them. This way i have access to the actual simulator without having to crawl underneath the car every time i want to reset something on the simulator. I can also see the LED light blinking - knowing the simulator is doing it's job. Plus is a lot cleaner and the simulator is protected from the outside factors.
Hope this helps.
I also checked/tested the wires to make sure i got the right ones with a voltmeter.
Is this what you have??</TD></TR></TABLE>
yes - that's what i got. I wired the O2 simulator to the O2 sensor wires going inside the car from underneath.
I pushed a metal rod from underneath through the rubber gasket in the floor, and by pulling on wires, i figured out which ones are the sensor wires. I sliced those buggers and i connected the O2 simulator to them. This way i have access to the actual simulator without having to crawl underneath the car every time i want to reset something on the simulator. I can also see the LED light blinking - knowing the simulator is doing it's job. Plus is a lot cleaner and the simulator is protected from the outside factors.
Hope this helps.
I also checked/tested the wires to make sure i got the right ones with a voltmeter.
10-18-2004, 08:07 AM
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Re: (PrettyLude)
I did the splicing of the wires according to the diagram
and that's exactly the way my sensor/simulator wires look right now
the left side - without the resistor
and that's exactly the way my sensor/simulator wires look right now
the left side - without the resistor
10-19-2004, 01:36 PM
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Re: (stefanne3)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by stefanne3 »</TD></TR><TR><TD CLASS="quote">yes ... I have the factory O2 sensor and i have the O2 simulator attached to the O2 sensor wires</TD></TR></TABLE>
What is the latest on this topic?? I've been having the same problem. I think it might be because the diagram had the "Heater GND" and the "Sensor GND" connected together....I don't believe they are the same point electrically. Try not connecting those points together........get power from the heater power connection and the ground from the sensor GND. Keep the heater power and heater GND connection connected to the O2 sensor....
Let me know what you find.
What is the latest on this topic?? I've been having the same problem. I think it might be because the diagram had the "Heater GND" and the "Sensor GND" connected together....I don't believe they are the same point electrically. Try not connecting those points together........get power from the heater power connection and the ground from the sensor GND. Keep the heater power and heater GND connection connected to the O2 sensor....
Let me know what you find.