Faking signals for emissions components.
12-16-2014 | 06:26 PM
#1
Thread Starter
Driving my unreliable rx8
Joined: Oct 2012
Posts: 2,051
Likes: 7
From: Alvarado, Tx
Faking signals for emissions components.
I'm trying to figure out how to keep from having to install the Air pump and/or the rear 02 sensor when it's time for the emissions check. In several states you can have one thing not ready and not be an issue. I have a accessport to cover up the cel, but would like to fake at least one signal so I don't have to install and wait for the test.
I am thinking I could use a LED load resistor across the Air pump so it will see something happening and not give the error.
I also found this which uses the power from the Air pump to send a lean signal to the ECU. I can run a output wire from my LC1 as the rear 02 sensor signal. Then possibility use a load resistor to simulate the heater.
I would appreciate any knowledge you electronics guys have. If you think it might not work for some reason or something that would work better. I do realize that the picture is for a car with 2 banks and I would only need one bank for the rear 02 sensor.
I am thinking I could use a LED load resistor across the Air pump so it will see something happening and not give the error.
I also found this which uses the power from the Air pump to send a lean signal to the ECU. I can run a output wire from my LC1 as the rear 02 sensor signal. Then possibility use a load resistor to simulate the heater.
I would appreciate any knowledge you electronics guys have. If you think it might not work for some reason or something that would work better. I do realize that the picture is for a car with 2 banks and I would only need one bank for the rear 02 sensor.
Last edited by logalinipoo; 12-16-2014 at 06:29 PM.
12-16-2014 | 06:33 PM
#2
Question: Why does blocking the CELs completely not work for you?
Mine were completely blocked, air pump disconnected and rear O2 missing, drove it like that daily, readiness monitors never showed a problem, passed OBD2 fine.
Otherwise, the rear O2 testing isn't just a switch. The ECU will periodically determine that it is time for another test, and will instruct the O2 sensor to behave in a certain way, and since it knows what the engine is doing from the MAF, load, RPM, and front O2 sensor, it expects the response to be in a specific range. If it's not, it will pop a CEL. That isn't something you can replicate with any sort of resistor.
I don't know if the air pump is tested in the same way.
Mine were completely blocked, air pump disconnected and rear O2 missing, drove it like that daily, readiness monitors never showed a problem, passed OBD2 fine.
Otherwise, the rear O2 testing isn't just a switch. The ECU will periodically determine that it is time for another test, and will instruct the O2 sensor to behave in a certain way, and since it knows what the engine is doing from the MAF, load, RPM, and front O2 sensor, it expects the response to be in a specific range. If it's not, it will pop a CEL. That isn't something you can replicate with any sort of resistor.
I don't know if the air pump is tested in the same way.
12-16-2014 | 06:42 PM
#3
Thread Starter
Driving my unreliable rx8
Joined: Oct 2012
Posts: 2,051
Likes: 7
From: Alvarado, Tx
My air pump never seams to go ready if I don't have it plugged in. It is just a motor with no response circuit. So I was mainly thinking a load resistor would simulate something being plugged in and it will go ready.
That's interesting you passed. I've never had mine go ready when disconnected. Carbonrx8 also had the same issue recently.
I haven't been without the rear o2 for long enough to know if it's a problem, but I am planing on sending it a true signal from the LC1 just in case the ecu actually uses it for something.
That's interesting you passed. I've never had mine go ready when disconnected. Carbonrx8 also had the same issue recently.
I haven't been without the rear o2 for long enough to know if it's a problem, but I am planing on sending it a true signal from the LC1 just in case the ecu actually uses it for something.
12-16-2014 | 06:46 PM
#4
I feel like we have had this conversation before, so stop me if you were the one i was talking to about it... 
There are two different locations in the maps that you have to turn off the CEL. One turns off the light, one turns off the ECU's ability to even check to see if it is a problem. If you turn off the light but not the test, then the code can still be sitting there and/or fail a readiness test. If you turn it off correctly, it will be as if the ECU is happy that it's always passing.
There are two different locations in the maps that you have to turn off the CEL. One turns off the light, one turns off the ECU's ability to even check to see if it is a problem. If you turn off the light but not the test, then the code can still be sitting there and/or fail a readiness test. If you turn it off correctly, it will be as if the ECU is happy that it's always passing.
12-16-2014 | 06:54 PM
#5
Thread Starter
Driving my unreliable rx8
Joined: Oct 2012
Posts: 2,051
Likes: 7
From: Alvarado, Tx
Not with me( i dont' think), but maybe, the only thing I've had disabled before is the cat code and that was never an issue for me.
I know mazdaedit has multiple places to hide CEL's. but I only have one for the accessport.
I know mazdaedit has multiple places to hide CEL's. but I only have one for the accessport.
12-16-2014 | 06:56 PM
#6
The maps are in the ECU, each device is just a method of accessing them. So both devices have the ability to manipulate them. In my case, it was through an AP, a few years before MazdaEdit was released.
*There are some maps that one has uncovered that the other hasn't, but none of them apply in this case to my knowledge.
*There are some maps that one has uncovered that the other hasn't, but none of them apply in this case to my knowledge.
12-16-2014 | 07:03 PM
#7
Thread Starter
Driving my unreliable rx8
Joined: Oct 2012
Posts: 2,051
Likes: 7
From: Alvarado, Tx
The current version of ATR might have combined the changes so instead of changing it in two different location, you make one change in the software and it changes both maps on the ECU simultaneously.
12-22-2014 | 08:52 PM
#8
U-Stink-But-I-♥-U
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From: 12 o'clock on the Beltway.
My air pump never seams to go ready if I don't have it plugged in. It is just a motor with no response circuit. So I was mainly thinking a load resistor would simulate something being plugged in and it will go ready.
That's interesting you passed. I've never had mine go ready when disconnected. Carbonrx8 also had the same issue recently.
I haven't been without the rear o2 for long enough to know if it's a problem, but I am planing on sending it a true signal from the LC1 just in case the ecu actually uses it for something.
That's interesting you passed. I've never had mine go ready when disconnected. Carbonrx8 also had the same issue recently.
I haven't been without the rear o2 for long enough to know if it's a problem, but I am planing on sending it a true signal from the LC1 just in case the ecu actually uses it for something.
Oh, Hey! wsup? I log back after a year and get 2000 posts. Today was a good day.
12-22-2014 | 10:13 PM
#9
Will not work, I also have looked deeply into this topic.
The readiness monitors work in sequence, the secondary air injection monitor is the 7th monitor to become active. Meaning if this monitor does not become active you will not get the last monitor to pass and will be stuck at 6/8 monitors. You need 7/8 to pass inspections.
Also the ECU looks as many things in regards to the secondary air pump monitor including
Air pump fuse/open circuit
Air pump solenoid actuation
Lean/rich conditions on the heated 02 during the first 5ms of startup
If the ECU does not detect the above to be functioning properly, it will not become active.
Masking the CEL will do nothing to change these conditions as they work independently. This is a solution I would pay dearly for.
The readiness monitors work in sequence, the secondary air injection monitor is the 7th monitor to become active. Meaning if this monitor does not become active you will not get the last monitor to pass and will be stuck at 6/8 monitors. You need 7/8 to pass inspections.
Also the ECU looks as many things in regards to the secondary air pump monitor including
Air pump fuse/open circuit
Air pump solenoid actuation
Lean/rich conditions on the heated 02 during the first 5ms of startup
If the ECU does not detect the above to be functioning properly, it will not become active.
Masking the CEL will do nothing to change these conditions as they work independently. This is a solution I would pay dearly for.
12-23-2014 | 02:29 AM
#12
Thread Starter
Driving my unreliable rx8
Joined: Oct 2012
Posts: 2,051
Likes: 7
From: Alvarado, Tx
12-23-2014 | 02:38 AM
#13
Thread Starter
Driving my unreliable rx8
Joined: Oct 2012
Posts: 2,051
Likes: 7
From: Alvarado, Tx
Will not work, I also have looked deeply into this topic. The readiness monitors work in sequence, the secondary air injection monitor is the 7th monitor to become active. Meaning if this monitor does not become active you will not get the last monitor to pass and will be stuck at 6/8 monitors. You need 7/8 to pass inspections. Also the ECU looks as many things in regards to the secondary air pump monitor including Air pump fuse/open circuit Air pump solenoid actuation Lean/rich conditions on the heated 02 during the first 5ms of startup If the ECU does not detect the above to be functioning properly, it will not become active. Masking the CEL will do nothing to change these conditions as they work independently. This is a solution I would pay dearly for.
Last edited by logalinipoo; 12-23-2014 at 02:43 AM.
12-23-2014 | 09:21 AM
#14
It will use stock o2 signal then go lean as soon as the air pump kicks on then go back to the signal when the pump goes off. Ive just capped the solenoid so its working as normal. I do not know what you mean by open fuse, but a resistor should show the demand so it thinks the pump is running. It very likely has the extra option in atr. Carbon, do you know the order of all the moniters?
ECU checks to to make sure the pump is physically plugged in by monitoring the current draw to the pump, you will need to match the actual pump's resistance at the plug.
Also I am not sure how technical the lean/rich monitor is as it will read pulses of lean signals not a constant when the pump is activated on off "Strokes"
You guys must have had better luck than I, I blocked P0420 and P0410 and after 800miles and 44 drive cycles the monitor never became active, nor did my o2 sensor as that is the last monitor and will not activate until the secondary air system does.
All this OBD crap, makes me wish I had an FD/FC instead.
12-23-2014 | 10:08 AM
#15
Thread Starter
Driving my unreliable rx8
Joined: Oct 2012
Posts: 2,051
Likes: 7
From: Alvarado, Tx
The pump ohms out at 7 ohms and the load resistor is 6. It might be that smart but i doubt it. I have the stuff to fake the 02 signal so i just have to buy a load for a few dollars.
Im pretty sure I'm gonna try it.
Im pretty sure I'm gonna try it.
12-23-2014 | 08:12 PM
#17
Shouldn't need a load resistor, something over 1kohm would probably work. You could probably figure out where the ecu taps off of and just drive a signal there. I don't have the time right now but when I do I'll take a look. The rear O2 sensor is really easy to spoof with an Arduino, the ECU cannot tell the difference.
12-25-2014 | 01:38 AM
#18
codes to block, note P0410 is only one of five AIR codes:
_________________
credit to MazdaMegamaniac for the list
P0030 Front HO2S heater control circuit problem
P0031 Front HO2S heater control circuit low
P0032 Front HO2S heater control circuit high
P0037 Rear HO2S heater control circuit low
P0038 Rear HO2S heater control circuit high
P0133 Front HO2S circuit slow response
P0138 Rear HO2S circuit high voltage
P0139 Rear HO2S circuit slow response
P0171 System too lean
P0172 System too rich
P0300 Random misfire detected
P0301 Front rotor misfire detected
P0302 Rear rotor misfire detected
P0410 AIR system problem
P0420 Catalyst system efficiency below threshold
P0441 EVAP system incorrect purge flow
P0442 EVAP system leak detected (small leak)
P0443 Purge solenoid valve circuit problem
P0446 EVAP system vent control circuit problem
P0455 EVAP system leak detected (large leak)
P0456 EVAP system leak detected (very small leak)
P2096 Target A/F feedback system too lean
P2097 Target A/F feedback system too rich
P2195 Front HO2S signal stuck lean
P2196 Front HO2S signal stuck rich
P2257 AIR pump relay control circuit low
P2258 AIR pump relay control circuit high
P2259 AIR solenoid valve control circuit low
P2260 AIR solenoid valve control circuit high
P2270 Rear HO2S signal stuck lean
P2271 Rear HO2S signal stuck rich
P2401 EVAP system leak detection pump control circuit low
P2402 EVAP system leak detection pump control circuit high
P2404 EVAP system leak detection pump sense circuit range/performance problem
P2405 EVAP system leak detection pump sense circuit low
P2406 EVAP system leak detection pump sense circuit high
P2407 EVAP system leak detection pump sense circuit intermittent/erratic problem
P0031 Front HO2S heater control circuit low
P0032 Front HO2S heater control circuit high
P0037 Rear HO2S heater control circuit low
P0038 Rear HO2S heater control circuit high
P0133 Front HO2S circuit slow response
P0138 Rear HO2S circuit high voltage
P0139 Rear HO2S circuit slow response
P0171 System too lean
P0172 System too rich
P0300 Random misfire detected
P0301 Front rotor misfire detected
P0302 Rear rotor misfire detected
P0410 AIR system problem
P0420 Catalyst system efficiency below threshold
P0441 EVAP system incorrect purge flow
P0442 EVAP system leak detected (small leak)
P0443 Purge solenoid valve circuit problem
P0446 EVAP system vent control circuit problem
P0455 EVAP system leak detected (large leak)
P0456 EVAP system leak detected (very small leak)
P2096 Target A/F feedback system too lean
P2097 Target A/F feedback system too rich
P2195 Front HO2S signal stuck lean
P2196 Front HO2S signal stuck rich
P2257 AIR pump relay control circuit low
P2258 AIR pump relay control circuit high
P2259 AIR solenoid valve control circuit low
P2260 AIR solenoid valve control circuit high
P2270 Rear HO2S signal stuck lean
P2271 Rear HO2S signal stuck rich
P2401 EVAP system leak detection pump control circuit low
P2402 EVAP system leak detection pump control circuit high
P2404 EVAP system leak detection pump sense circuit range/performance problem
P2405 EVAP system leak detection pump sense circuit low
P2406 EVAP system leak detection pump sense circuit high
P2407 EVAP system leak detection pump sense circuit intermittent/erratic problem
credit to MazdaMegamaniac for the list
12-26-2014 | 10:51 AM
#20
Don't know what I was thinking the other day. The REAR O2 sensor drives the P0410 CEL, nothing else does. There is no need for a load resistor, but you do need to leave the air solenoid and the Relay intact if you remove the pump. Disconnecting the rear o2 and blocking the CEL will block the P0410 as well, that's how I have mine setup and I've never had a AIR pump related CEL. I do have a mystery o2 sensor CEL that came in after I installed the turbo, but I'm still investigating that one.
Hope that helps.
Hope that helps.
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