need Evo 9 owner to test rear O2 *heater* sim patch
The Rear O2 Heater Sim Patch is specifically for people who have removed their rear O2 sensor completely. Previously, if you wanted to remove your rear O2 sensor and not get a check engine light, you had two options:
1.) Apply a Rear O2 Signal Simulator and then install a resistor to simulate a valid heater signal
2.) Disable the ECU Periphery bit that controls the Rear O2 tests
Option 1. is a must for people that need to pass inspection in the US, because when you disable the rear O2 tests, you fail the OBD Readiness test. Thus, the Heater sim is a way for people to not have to wire in a resistor, and still be able to leave the rear O2 tests enabled for passing inspection.
Acamus has provided an alternative to having to simulate the rear O2 heater signal... and that is finding the subroutines that respond to the OBD test requests and setting them all to "Pass". In this respect, you should be able to just disable any tests you want (rear O2, EGR, etc) and still pass inspection by always sending back "Pass" when a test is probed.
1.) Apply a Rear O2 Signal Simulator and then install a resistor to simulate a valid heater signal
2.) Disable the ECU Periphery bit that controls the Rear O2 tests
Option 1. is a must for people that need to pass inspection in the US, because when you disable the rear O2 tests, you fail the OBD Readiness test. Thus, the Heater sim is a way for people to not have to wire in a resistor, and still be able to leave the rear O2 tests enabled for passing inspection.
Acamus has provided an alternative to having to simulate the rear O2 heater signal... and that is finding the subroutines that respond to the OBD test requests and setting them all to "Pass". In this respect, you should be able to just disable any tests you want (rear O2, EGR, etc) and still pass inspection by always sending back "Pass" when a test is probed.
Is the 0031 CEL always just the heater test? and why does it fail? Mine didn't fail for a long time, and now does.
Or could that code represent other issues and symptomize in a 0031?
I guess I am trying to figure out the very first piece, which is, Why are we getting the heater CEL?
I know I am a bit OT for this thread, but nobody answered anything on my separately created thread. However I will provide any testing if anyone wants me to. Though you may have to answer my dumb questions.
Thanks for the help.
M
Evolving Member
Joined: Jun 2007
Posts: 156
Likes: 0
From: NorCal
Most people are getting the heater cel because they have disconnected the rear O2 sensor for whatever reason and the resistance for the O2 heater circuit is no longer correct. I took my rear sensor out to run a wideband in its place and had to do a resistor mod to correct the heater cel. Which no longer have to do thanks to Mr. Fred and Tephra.
Aha, What is the next most common reason people would be getting the 0031?
Thats what I was trying to find on the forum. I installed a Wideband, but welded in an additional bung in the DP. So I can run all of the 02s.
The other question that goes with that is that I was lead to believe from reading that both 02s are needed for the ECU to manage AFR in open loop. So the idea of removing the rear 02 seemed surprising.
Thats what I was trying to find on the forum. I installed a Wideband, but welded in an additional bung in the DP. So I can run all of the 02s.
The other question that goes with that is that I was lead to believe from reading that both 02s are needed for the ECU to manage AFR in open loop. So the idea of removing the rear 02 seemed surprising.
Only the front O2 is used for feedback. The rear O2 is simply to check the operation of the catalyst and the front O2.
Got it. Its coming together for me now. Any ideas why I would get a 0031 now after months of none, and no change to the car physically or tune (flash).
Would I fire that 0031, just because I don't have a cat? If I clear the code it comes back in like 15 to 20 minutes. Does that indicate anything?
Any suggestion on which, if any, of these methods to use to eliminate the 0031 code, eventhough I can/will retain the rear 02.
Would I fire that 0031, just because I don't have a cat? If I clear the code it comes back in like 15 to 20 minutes. Does that indicate anything?
Any suggestion on which, if any, of these methods to use to eliminate the 0031 code, eventhough I can/will retain the rear 02.
Evolving Member
Joined: Jun 2007
Posts: 156
Likes: 0
From: NorCal
I would bet that your rear O2 heater circuit has gone bad i.e. broken O2 sensor. Which could indicate why the cel comes back a few min. after you clear it.
I would use Mr. fred's rear O2 heater sim if you just want to eliminate the CEL.
I would use Mr. fred's rear O2 heater sim if you just want to eliminate the CEL.
Last edited by krazykorean84; Mar 2, 2009 at 11:40 AM.
It didn't work.....now all the monitors are shown as not supported including the continuous ones. I tried last night and re-checked everything and re-flashed again this morning and the same thing.....
I also posted a brief summary of what I think I learned if some need a dumbed down review. Thkx for letting me OT for bit to get caught up.
https://www.evolutionm.net/forums/ec...ming-back.html
M
Evolved Member
Joined: Mar 2008
Posts: 730
Likes: 3
From: Lattitude 48.38°, Longitude 17.58°, Altitude 146m = Slovakia, for common dude
For CEL removal, you have to ask mrfred for his part or tephra to include in V6.
Here come inspection bits for 94170015 '04 EVO8 USDM,
First apply the patches:
Non-Continuous Monitor Completion Patch
@3688E DA2A -> EAFF
@36890 6AA1 -> 6AA7
Non-Continuous Monitor Availability Patch Part 1
@36872 4019 -> E000
Non-Continuous Monitor Availability Patch Part 2
@36888 6AA1 -> EAFF
Once done one can use following definition:
Here come inspection bits for 94170015 '04 EVO8 USDM,
First apply the patches:
Code:
<table name="Non-Continuous Monitor Availability Patch Part 1" category="OBD Inspection" address="36872" type="1D" level="1" scaling="Hex16"/> <table name="Non-Continuous Monitor Availability Patch Part 2" category="OBD Inspection" address="36888" type="1D" level="1" scaling="Hex16"/> <table name="Non-Continuous Monitor Completion Patch" category="OBD Inspection" address="3688E" type="2D" level="1" scaling="Hex16"> <table type="Static Y Axis" elements="2"> <data>3688E</data> <data>36890</data> </table> </table>
@3688E DA2A -> EAFF
@36890 6AA1 -> 6AA7
Non-Continuous Monitor Availability Patch Part 1
@36872 4019 -> E000
Non-Continuous Monitor Availability Patch Part 2
@36888 6AA1 -> EAFF
Once done one can use following definition:
Code:
<table name="Monitor Available(1)/Not Available(0)" category="OBD Inspection" address="36889" type="2D" level="2" scaling="blobbits"> <table name="Non-Continuous Monitor Availability Bits" type="Static Y Axis" flipy="true" elements="8"> <data>EGR system</data> <data>Oxygen heater sensor</data> <data>Oxygen sensor</data> <data>A/C system refrigerant</data> <data>Secondary air system</data> <data>Evaporative system</data> <data>Heated catalyst</data> <data>Catalyst</data> </table> </table> <table name="Monitor Passed(1)/Failed(0)" category="OBD Inspection" address="3688F" type="2D" level="2" scaling="blobbits"> <table name="Non-Continuous Monitor Completion Bits" type="Static Y Axis" flipy="true" elements="8"> <data>EGR system</data> <data>Oxygen heater sensor</data> <data>Oxygen sensor</data> <data>A/C system refrigerant</data> <data>Secondary air system</data> <data>Evaporative system</data> <data>Heated catalyst</data> <data>Catalyst</data> </table> </table>
Does anyone have a link to the resister patch mod, "how to"? I don't have access or the know how to do the rom changes on my VIII, so I need a physical patch for now as my rear o2 is throwing the heater CEL.
I've been searching for it for hours and I can't find it.
I've been searching for it for hours and I can't find it.
Evolving Member
Joined: Jun 2007
Posts: 156
Likes: 0
From: NorCal
This is the link but you still have to do some rom modification. I would really just go with Mr. Fred's patch. Just read all the info, its not that hard to figure out.
https://www.evolutionm.net/forums/ec...heres-how.html
https://www.evolutionm.net/forums/ec...heres-how.html
Thanks a ton.. I've actually got one of the Rom mods installed by a good friend, but it did not seem to work, few days after the tephra V5 mod was installed the o2 sensor went wack and threw a code. Does V6 actually cure this?
Sorry for taking so long to get this posted. A *stock* patched 88590015 ROM and the accompanying xml definitions are in the link below. Add the definitions to your ECUFlash 88590015 definition file, open your current ROM, and then copy the table values from the stock patched ROM to your current ROM. Flash to your ECU and no more rear O2 heater CEL.
tephra, do you want me to email you a copy of the source code?
http://se30.dyndns.org:8080/EVO/8859...CEL_fix_v1.zip
tephra, do you want me to email you a copy of the source code?
http://se30.dyndns.org:8080/EVO/8859...CEL_fix_v1.zip
I have the rear02 in the car, no cat, and its throwing P0031 a bit after clearing the code. At first the patch seemed to work right away, and the CEL didn't come back until a day later (about an hour of driving or less).
Any ideas? Or anything i can provide that would assist.
M
Anyone? Is it appropriate to use this Heater Sim even though I still have the 02 sensor in the car?
Any other directions I could try to avoid the 0031 CEL?
(Yes it took me less time to replace the clutch than I have spent so far NOT fixing this damn 0031 CEL)
Any other directions I could try to avoid the 0031 CEL?
(Yes it took me less time to replace the clutch than I have spent so far NOT fixing this damn 0031 CEL)
Last edited by fireroasted; Mar 7, 2009 at 01:55 PM.