Air Fuel (A/F) Sensor P0030 | Testing and Replacement

Today we'll be testing and replacing an air fuel sensor. (Upstream sensor 1.) Also known as A/F sensors, these are a bit more sophisticated than oxygen sensors found in older vehicles. Nonetheless, both sensors are able to indicate air fuel ratios. This specific vehicle is a 2010 Subaru Impreza non-turbo.
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Common Trouble Codes:
P0030 - Bank 1 Sensor 1, control circuit
P0031 - Bank 1 Sensor 1, circuit low
P0032 - Bank 1 Sensor 1, circuit high
P0131 - Bank 1 Sensor 1, low voltage
P0132 - Bank 1 Sensor 1, high voltage
P0133 - Bank 1 Sensor 1, slow response
P0134 - Bank 1 Sensor 1, no activity detected
P1152 - Bank 1 Sensor 1, circuit range / performance high
P1153 - Bank 1 Sensor 1, circuit range / performance high
Note:
Any attempt to repair automotive parts and/or systems carries risk of personal injury. Always adhere and follow safe practices when working on vehicles. Such as, safety glasses, jack stands, no loose clothing, etc. No guarantee or warranty is implied. Use the information in this video at your own risk. Carsntoys is a member of the Amazon Influencer Program.
Publication, reproduction or distribution of this film is strictly prohibited.
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#afsensor #airfuelsensor #p0030

[@vaughancosbie-ross8126]

Probably one of the best and most helpful videos I have watch on here. Thank you and very well done.

[@DJ-mo2ur]

the cooling fans come out real easy and makes the job easier yet

[@strueplay]

Great video. I need to change my o2 sensor on my 2012 forester and this is exactly what I was looking for!

[@CarsNToys]

Awesome. Glad to help.

[@Alex-jm6fk]

None of the tests shown in this video will confirm that the sensor is good or bad. To properly test AF sensor operation, you need a scan tool that shows the sensor voltage. Force the mixture rich and lean and verify that the sensor voltage responds accordingly as well as the fuel trims.

[@justing9902]

all he showed was testing the o2 heater, he didnt mention most cars with a 4 pin o2 will have 2 wires the same color, n those r the o2 heater usually. someones gonna ruin a o2 sensor watching this video haha

[@Alex-jm6fk]

@Joe Average yes you need to check integrity of the circuits to the sensor. But the title of this video suggests he is showing you how to test an AF sensor. He is showing you nothing about how to test the sensor, only how to test the circuit to the sensor.

[@BONFIRERG]

this is so clear .. thumbs up

[@who8dapple]

So, I confirmed continuity with AF Sensor, and its good. I also checked the source and was getting 12.34 dcv. But it's still throwing a P0300 Heated oxygen sensor (HO2S) 1, bank 1, heater control - circuit malfunction code...what else is going on?

[@seshachary5580]

VERY NICE. THANK YOU REGARDS

[@adanarceo4636]

Very nice demonstration, but I think those test not always precise. I just replaced 2 02 sensor that was reading 3.5HMS, and they were bad. I assume that the heater element was shot,regardless the good readings. Thanks for sharing.

[@Glenn_123]

Excellent video!

[@CarsNToys]

Thank you.

[@victornaja7927]

What are normal reading on a scanner for af ratio sensor.

[@Benny-dv7xm]

So why are the voltages on the other leads because my Zurich s13 was reading the 2.156v with nominal switching back and forth between 2.151v. I disconnected the connectors and the scan tool was still reading the same 2.156v on the AFR sensor and the lambda was close to 1 but the rear O2 sensor will not work without the front circuit and the short term fuel trim will go away high with no long term fuel trim being indicated and then it just stops displaying any fuel trims. With heater circuit codes on my 2004 Subaru Forester X 2.5l w/automatic afr why does the computer revert to like if the engine is cold instead of first as if the engine is warm coming off the highway after only approximately 10 minutes and it operates much leaner in idle until I shut it off for a few seconds and then it goes into the crappy super rich rough running start-up mode. The one day I tested it in idle for (2) hours after coming off the highway and it ran much leaner and that was when it was winter. So where can we get a book that actually has the logic and normal sequences and alternative sequences when there are problems as seen from the computers side for these damned computers because it is not making any sense why it shouldn't default to closed loop or open loop drive to get to leaner mode. 3 to 6 mpg currently but my # 1cylinder reads 197 psi and only leaked down to 195 psi after 20 minutes so some of the cylinders are good and so the motor should be running leaner when we look at it from motor mechanics stance.

[@joaodiogo962]

I can't find my Air Fuel Sensor on my Hyundai Accent 2016 Model, can you help me?

[@1949carguy]

I am working on a 2010 Forester. Getting P0031 and P0037 on both sensors. Car runs perfectly. Is there a fuse or relay that supplies power to these sensors. I am really stumped

[@1949carguy]

I did measure voltage at both plugs and there isn't 12 volts at either.

[@christiangraham4579]

Steve Rothman your codes have to do with the heater circuit. The heater circuit heats up the O2 sensors to get the vehicle to go into closed loop faster(closed loop is when the operating values are close enough to actually adjust fuel trim from the sensors) open loop is a base tune(values) for cold starts to warm things up faster and keep the engine from wearing too much. Along with emission reasons. These codes will only be thrown for three reasons, bad sensor, wiring issues, or the ecm. Good luck! (Probably gonna need both sensors.) assuming your vehicle has 80k+

[@Tino-gw1iu]

I see same problem on my legacy. I changed bank1 sensor2 with fiat palio o2 sensor. Same sensor but not same socket. Cut old sensor wires and solder it new sensor with same color. Its ok😁

[@JamesAutoDude]

Video starts at 2:45

[@rhadzelibrahim6363]

I have a problem with my accent. P0030 always comes out even though I change already my 02 sensor1 bank1. I already change the codes but still the check engine still comes out

[@Nightrunnergunner]

great step by step breakdown. ive been looking for this kind of video on youtube! so my top o2 Sensors on my 2016 dodge dart has 2 wires that are slightly stripped/ripped. ive been driving my car for about 4 months w/o having replaced it yet.(i will soon) but what kind of damage or concerns should i be worried about? i havent noticed much a differemce execpt laggy throttle response, les mpg and a smelly sound on start up

[@CarsNToys]

Thank you. Typical symptoms are: lack of power, hesitation, engine stall, rough idling and excessive fuel consumption.

[@christiangraham4579]

Giovanni Arohsiri you’ll run rich and that can ruin all of the other O2 sensors and the cat. Also over long periods of time it can cause wear on the cylinder walls and thin the oil a bit. You may also melt your cats and start a fire. Lol happened to my buddy. Same situation, wires stripped out, causing excess fuel in cat it will super heat and melt eventually

[@christianwoodley7699]

Can someone please help. I have a 2006 Suburu Impreza R with a 2010 Impreza engine in it. It’s throwing the code P0031 (heated O2 sensor circuit low bank 1 sensor 1). I’ve tested the harness for power with the ignition on and gotten 12.8 V and then the resistance on the sensor with a reading of 2.2 Ohms. What else could be causing the problem? It’s driving me nuts. The engine struggled for power under 3K rpm in 1st-3rd gear. I reset everything and cleared the code to see if it did anything and now the car is running like it’s brand new, the P0031 code is back as a pending code however it’s no longer causing a CEL on the dash. What other diagnostics can I do?

[@Ctheflow]

Could be a short in the ecu.. my 11 Impreza did that and my mechanic had to take apart the ecu and solder some stuff in there. There's no test you can perform to find out as all the voltages are fine and everything looks to be working properly. But if you look closer some of the voltages are just slightly off and it's because of a short inside the ecu. It's a pain as my car just started doing the same thing after I already tried replacing the a/f sensor the first time it happened so I'm hoping my ecu is acting up again.

[@justing9902]

the o2 sensor heater should be between 5-20 ohms the 2 wires that r the same color on the o2 sensor itself are the heater wires on most cars

[@azizlenox]

Did you sand it or clean it?

[@CarsNToys]

Neither. You never want to touch the element. It will completely ruin the sensor.

[@alex.777riquelme5]

CarsNToys limpiar con limpia contactos electricos? clean with clean electrical contacts?

[@dadabg8747]

and that's my problem. my dumb ass put 90% alcohol on it 🤦🏾‍♂️

[@RADIOSCATRACHASUTAN]

If you see 3 vots on it? I have this volvo s40 with O2 sensor error codes, they suppossed to be fed with battery voltage right?

[@madmechanic7976]

No they create their own voltage signal.

[@bulleybeatz201]

Does this fix my A/C ??

[@CarsNToys]

No. An emissions component.

[@rameshwarmisal6087]

i20 ka sisar kimt bato

[@jangonzalez5627]

I got p0030 on my 03 subaru legacy and i reapleaced both o2 sensors already any help