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Make sure that the air-fuel sensor is an OEM or compatible one that works properly and not a counterfeit part. Some aftermarket ones don't work correctly. Make sure the connector is plugged in all the way and that it clicks in. Also, verify that none of the fuses for the heater circuit is blown. If everything checks out OK the last thing to check is the connector on the computer side where you plug the air-fuel sensor in. You will have to check the pins from one end to the other end to the computer side to see both are getting proper resistance and powers and grounds, etc. You will need to get a pinout view/diagram to know which pins to check from both ends. If everything checks out OK then it is possible that the computer is bad (PCM/ECM). If the pins/wiring don't check out OK then you will need to repair the wiring to fix this problem. I hope this doesn't sound too complicated. If this is outside your realm of diagnostics/repairs then you will need to take the vehicle to a reputable mechanic shop to have your vehicle repaired properly.
If it is for the regular 2.5 Forester and not the turbocharged one and you have the same problem for Bank 1 Sensor 1 then here are the part numbers you can go by either: NTK 24851 OR DENSO 2349109. These are for the upstream sensor or air fuel sensor for bank 1 sensor 1. I would recommend either the Denso or NTK parts.
I had a P0031 error on a Forester (same engine). I changed the O2 sensor but still have the error code showing. Do you have any suggestions on what I should try next?
Did you check the data PIDs before replacing the old o2 sensor to see if there was any activity? What kind of replacement o2 sensor did you use for the new one? Typically non OEM or non recommended sensors will cause problems. Usually Denso or NTK work fine. Also, be careful of counterfeit parts if you bought from Amazon or some other unsuspecting places. If you're still getting the trouble code I would check the fuse and relay if there are any for the system. Lastly, you would need to check the wiring at the computer. You will need a wiring diagram and a pin out diagram to continue diagnosis. You will need to check the wires for powers and grounds and possibly for resistance to make sure you are getting proper readings from one end to the other end of the wires. Start with a visual inspection to see if there are any corrosion or broken wires. If the o2 sensor part and fuses and relays are OK then you either have a wiring or a computer issue. So you would need to check all of that to see if the computer or wiring is bad.
No, because the vehicle still needs to be diagnosed properly. It is not always an o2 sensor issue. It is not a matter of pulling a code and replacing a part. It doesn't work that way. Vehicles always needs to be diagnosed first.
@@moosemobileautorepair In my case code was loose o2 sensor connector after replacing sensor, so it's a reasonable assumption. In any case video was great as it alerted me to the problem.
Thanks, but realize you cannot make assumptions when diagnosing or working on cars. You have to be sure the vehicle is diagnosed correctly, otherwise it's just guessing. If it's your own car it may not be a big deal, but that is what I learned through experience over the years. Glad you were able to fix the problem.
If you enjoyed this video and found it helpful please support my channel by hitting the LIKE 👍and SUBSCRIBE buttons and turning on the bell notifications to get notified when I put out a new video.
Hey brother changed sensor but still same code. Any thoughts?
Make sure that the air-fuel sensor is an OEM or compatible one that works properly and not a counterfeit part. Some aftermarket ones don't work correctly. Make sure the connector is plugged in all the way and that it clicks in. Also, verify that none of the fuses for the heater circuit is blown. If everything checks out OK the last thing to check is the connector on the computer side where you plug the air-fuel sensor in. You will have to check the pins from one end to the other end to the computer side to see both are getting proper resistance and powers and grounds, etc. You will need to get a pinout view/diagram to know which pins to check from both ends. If everything checks out OK then it is possible that the computer is bad (PCM/ECM). If the pins/wiring don't check out OK then you will need to repair the wiring to fix this problem. I hope this doesn't sound too complicated. If this is outside your realm of diagnostics/repairs then you will need to take the vehicle to a reputable mechanic shop to have your vehicle repaired properly.
@@moosemobileautorepair not at all brother I'll start checking em off the list ty!
Do you have the part number for this on a 2008 Subaru Impreza 2.5i? I also have a low bank 1 sensor 1 P0031 code
NTK 24696
Thank you for the video, I have a Forester Subaru 2011 the same problem, but I don't know the part number of the sensor , could you help me?
If it is for the regular 2.5 Forester and not the turbocharged one and you have the same problem for Bank 1 Sensor 1 then here are the part numbers you can go by either: NTK 24851 OR DENSO 2349109. These are for the upstream sensor or air fuel sensor for bank 1 sensor 1. I would recommend either the Denso or NTK parts.
Thanks for this. I appreciate that you did troubleshooting to establish the cause of the error code. Where did you get the online diagrams
Thanks. I used All Data or Identifix for service information.
Check the 2 15amp fuses under the dash on the passenger side
Hay subaru legacy b4 2.5l 2008 p0131 02 sensor circuit low voltage bank1 sensor 1 place help???
I had a P0031 error on a Forester (same engine). I changed the O2 sensor but still have the error code showing. Do you have any suggestions on what I should try next?
Did you check the data PIDs before replacing the old o2 sensor to see if there was any activity? What kind of replacement o2 sensor did you use for the new one? Typically non OEM or non recommended sensors will cause problems. Usually Denso or NTK work fine. Also, be careful of counterfeit parts if you bought from Amazon or some other unsuspecting places.
If you're still getting the trouble code I would check the fuse and relay if there are any for the system. Lastly, you would need to check the wiring at the computer. You will need a wiring diagram and a pin out diagram to continue diagnosis. You will need to check the wires for powers and grounds and possibly for resistance to make sure you are getting proper readings from one end to the other end of the wires.
Start with a visual inspection to see if there are any corrosion or broken wires.
If the o2 sensor part and fuses and relays are OK then you either have a wiring or a computer issue. So you would need to check all of that to see if the computer or wiring is bad.
The shortcut answer is P0031 is bad front o2 sensor.
No, because the vehicle still needs to be diagnosed properly. It is not always an o2 sensor issue. It is not a matter of pulling a code and replacing a part. It doesn't work that way. Vehicles always needs to be diagnosed first.
@@moosemobileautorepair In my case code was loose o2 sensor connector after replacing sensor, so it's a reasonable assumption. In any case video was great as it alerted me to the problem.
Thanks, but realize you cannot make assumptions when diagnosing or working on cars. You have to be sure the vehicle is diagnosed correctly, otherwise it's just guessing. If it's your own car it may not be a big deal, but that is what I learned through experience over the years. Glad you were able to fix the problem.