Resistor to replace stock o2 sensor?
Feb 19, 2012, 07:45 AM
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Resistor to replace stock o2 sensor?
Hi, I need to replace a faulty stock o2 sensor with a resistor. (I'm not using the sensor, so I'd rather spend 50 cents on a resistor than a hundred on a new sensor)
I've tried 8 ohms and 16 ohms and I get P0031 - Circuit Low.
Does anyone know what the resistance level is supposed to be?
-------************** Editing to add answer**************------------
I was connecting the wrong wires together. On the 2008 Evo X GSR, the real heater circuit is black wire to black wire. I ended up using 16 ohms for the resistance.
Another update...
The 16 ohm solution I posted does not get rid of the problem codes.
None of the resistor values I tried - 5,6,7,8,16 got rid of the code.
I finally gave in and got a replacement O2 sensor. This also did not get rid of the code. I called the parts guy and he sent me a replacement (nice work Rock Auto) but the replacement had the same problem. Rock Auto told me to get my ECM diagnosed.
I went to the local shop here and they tinkered with it and eventually figured out that the "historical data" needed to be reset in the ECM. This appears to have fixed the codes.
So it may be that the resistor works, but you need to reset the ECM properly to prevent codes?
Now I only wish the shop hadn't put 26 mysterious miles on it...
I've tried 8 ohms and 16 ohms and I get P0031 - Circuit Low.
Does anyone know what the resistance level is supposed to be?
-------************** Editing to add answer**************------------
I was connecting the wrong wires together. On the 2008 Evo X GSR, the real heater circuit is black wire to black wire. I ended up using 16 ohms for the resistance.
Another update...
The 16 ohm solution I posted does not get rid of the problem codes.
None of the resistor values I tried - 5,6,7,8,16 got rid of the code.
I finally gave in and got a replacement O2 sensor. This also did not get rid of the code. I called the parts guy and he sent me a replacement (nice work Rock Auto) but the replacement had the same problem. Rock Auto told me to get my ECM diagnosed.
I went to the local shop here and they tinkered with it and eventually figured out that the "historical data" needed to be reset in the ECM. This appears to have fixed the codes.
So it may be that the resistor works, but you need to reset the ECM properly to prevent codes?
Now I only wish the shop hadn't put 26 mysterious miles on it...
Last edited by didalos; Apr 13, 2012 at 06:47 AM. Reason: add answer
Feb 19, 2012, 09:53 AM
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Other route
Or, if anyone can take a probe to the heater circuit on their stock o2 sensor and tell me the current that would give me the answer. I can't do it myself because my stock sensor isn't working.
The heater wire is the white one, and its ground is counterclockwise from it, looking at the wire connection on the sensor.
The heater wire is the white one, and its ground is counterclockwise from it, looking at the wire connection on the sensor.
Feb 20, 2012, 07:03 AM
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That info is for the IX. Does anyone know if it applies to the X?
It says this:
"This ECU circuit requires an ohm load between 1.1 and 80 to keep the CEL from coming on"
So, seems like 8 ohms meets that criteria. I don't have the ability to do step 2 with modifying the ECU, but again, not sure that it applies to the X.
It says this:
"This ECU circuit requires an ohm load between 1.1 and 80 to keep the CEL from coming on"
So, seems like 8 ohms meets that criteria. I don't have the ability to do step 2 with modifying the ECU, but again, not sure that it applies to the X.
Feb 20, 2012, 10:22 AM
#5
That info is for the IX. Does anyone know if it applies to the X?
It says this:
"This ECU circuit requires an ohm load between 1.1 and 80 to keep the CEL from coming on"
So, seems like 8 ohms meets that criteria. I don't have the ability to do step 2 with modifying the ECU, but again, not sure that it applies to the X.
It says this:
"This ECU circuit requires an ohm load between 1.1 and 80 to keep the CEL from coming on"
So, seems like 8 ohms meets that criteria. I don't have the ability to do step 2 with modifying the ECU, but again, not sure that it applies to the X.
i believe the resistor part is for the simulating the o2 heater only. using the resistor should keep the o2 heater code from being thrown.
HOWEVER, if you remove the o2 sensor and do not disable the rear o2 sensor via the ECU, then you will throw a code or two related to a missing rear o2. i assumed you disabled your rear o2 when you said you werent using the sensor.
Feb 20, 2012, 11:48 AM
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I think is is not only about the resistance, but also about the power (in Watts) of the resistor, as there flows pretty high current through the heating curcuit.
Feb 20, 2012, 01:21 PM
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The stock part numbers between the IX and the X are different.
The ECU is receiving a simulated O2 signal to keep it happy. So yes, I'm just trying to overcome the heater circuit warnings.
Current, power, and resistance are all relational, so if I can get the spec for any of those values, I will know what the resistance needs to be. (because voltage is known)
The ECU is receiving a simulated O2 signal to keep it happy. So yes, I'm just trying to overcome the heater circuit warnings.
Current, power, and resistance are all relational, so if I can get the spec for any of those values, I will know what the resistance needs to be. (because voltage is known)
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Feb 23, 2012, 08:46 AM
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Do you still have 1 working O2 sensor? You should be able to measure resistances on that one. Make sure it is hot and such. Be careful working around hot parts.
shouldn't hurt anything i'd be surprised if 40ohms doesn't do it
Feb 23, 2012, 10:00 AM
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The working O2 sensor I have is different from the stock one, so it's unclear how similar its resistance would be. (Also for lack of tools and no desire to mess with the working sensor's wires)
My plan right now is to order a pile of resistors and divide and conquer.
My plan right now is to order a pile of resistors and divide and conquer.
Feb 23, 2012, 07:44 PM
#14
i might test this for you next week, possibly this weekend if i get some time. i would like to know the voltage, resistance, and current of the stock o2 heater as well and i want to compare to the AEM uego's heater.
i can tell you with the sensor out of the car, the resistance is between the two black wires is 6.5 Ohms
are you sure the white wire is heater?? all denso 4 wire o2 sensors seem to be
blue - signal
ground - white
black - heater
black - heater
do you have any plans for your broken o2 sensor?
i can tell you with the sensor out of the car, the resistance is between the two black wires is 6.5 Ohms
are you sure the white wire is heater?? all denso 4 wire o2 sensors seem to be
blue - signal
ground - white
black - heater
black - heater
do you have any plans for your broken o2 sensor?
Last edited by momostallion; Feb 23, 2012 at 08:02 PM.
