[DougGuy]

I got my first replacement o2 sensors from Rock Auto in Feb of 2020, they were the economy models $51.79 each. They lasted just until the warranty ran out on them and now I got a service engine light.

ULTRA-POWER 2349038 {#226931AA0A, 226938W90A} (Economy)
UPSTREAM LEFT; UPSTREAM RIGHT.

Do you prefer a particular brand or part number, and do you get better mileage with a particular brand?

Also, correct me if I am wrong, the upstream sensors are the O2, and the down stream sensors are for air/fuel monitor?

At this point, I am likely going to replace them with a slightly more expensive unit, also from Ultra Power. I don't see the sense in spending 2x or 3x more money on a name brand if the mileage will remain basically the same.

Maybe some of you have better input on this topic than I have, which is why I am asking your opinions.

 

[mtnbound]

what code is coming up? are you sure its the o2's and not the cats?

 

[545]

Oxygen sensors are rarely the issue

if you do replace any, replace upstream and downstream with the same brand

Use denso sensors

 

[Lowcountry idn]

So on an 08 the upstream are A/F sensors, and the downstream are heated oxygen sensors.

If your sensor is keeping your long term fuel trims in check - ie +/- 5% or lower, then it shouldn't affect gas mileage at all.

If you got a P0420 or P0430 cat code, its most likely the cat, not the sensor.

If you got a P017x code it might be the sensor, or many other things like a vacuum leak, exhaust leak, leaky injector, etc.

The OEM sensors are Denso, and that is what I used for replacements as well. There about $80.00 at reputable online sellers.

I only use parts from OEM type suppliers - ie Denso, hitachi, TRW, Bosch, Ina, etc. I don't use jobber parts - like duralast, Dorman, ultra power, etc. Most of those places don't actually build parts - they send a competitor part to China and have some contract manufacturer make it for them. Sometimes they work, often they do not.

 

[mtnbound]

I just replaced the pass primary cat and now just got a p1148, im going to check for exhaust leaks around the primary cat and if i dont find any replace the pass side primary o2.

 

[DougGuy]

Last time I checked, the code was P0430, the engine light goes out after a long drive, but comes back on after driving in town.

My vehicle had 139k on it when I bought it with a bad knock in the engine. I had swapped in a used VQ40DE engine with 82k on it at 139k, I put brand new Bosal primary cats on at 140k mi, I think it is at 162k now, so 22k mi and the cat is bad?

The engine runs great, gets good mileage, and doesn't use oil.

 

[westslope]

From memory, the OEM AF

....
If you got a P0420 or P0430 cat code, its most likely the cat, not the sensor.

I will second that. Question: Could leaks in the exhaust system cause a P0420 or P0430 code.

I only use parts from OEM type suppliers - ie Denso, hitachi, TRW, Bosch, Ina, etc.

I recall a poster or two saying that the OEM A/F sensors in their 2005 and 2006 rigs were made by Bosch. I have replaced both on my 2006 X with Denso and Hitachi.

I also recall a poster mentioning that the range of output varied between these A/F sensors.

Both Denso and Hitachi A/F sensors in the Bank 2, Sensor 1 location will generate 1.29 volts upon a radical deceleration but otherwise operate normally. Unfortunately, I was not observing A/F, O2 sensors and fuel trims prior to switching in the Denso A/F sensor several years ago.

I had the regional Nissan Dealership switch in Eastern primary cats in October. That was a bit of a disaster and I will post on that later. Within a couple of trips, I had a Pending Fault Cod P2A03 for Bank 2 Sensor 1. It could be an exhaust leak, fuel injector or intake leaks according to what I read here.

In addition to rechecking the grounds and exhaust leaks, I will start by checking the B2S1 A/F sensor and will replace with a Bosch sensor to see if the reported voltage range stays under 1.0.

 

[Lowcountry idn]

From memory, the OEM AF

I will second that. Question: Could leaks in the exhaust system cause a P0420 or P0430 code.

I recall a poster or two saying that the OEM A/F sensors in their 2005 and 2006 rigs were made by Bosch. I have replaced both on my 2006 X with Denso and Hitachi.

I also recall a poster mentioning that the range of output varied between these A/F sensors.

Both Denso and Hitachi A/F sensors in the Bank 2, Sensor 1 location will generate 1.29 volts upon a radical deceleration but otherwise operate normally. Unfortunately, I was not observing A/F, O2 sensors and fuel trims prior to switching in the Denso A/F sensor several years ago.

I had the regional Nissan Dealership switch in Eastern primary cats in October. That was a bit of a disaster and I will post on that later. Within a couple of trips, I had a Pending Fault Cod P2A03 for Bank 2 Sensor 1. It could be an exhaust leak, fuel injector or intake leaks according to what I read here.

In addition to rechecking the grounds and exhaust leaks, I will start by checking the B2S1 A/F sensor and will replace with a Bosch sensor to see if the reported voltage range stays under 1.0.

I had an P2A03 code on a 6 month old denso sensor - turned out to be a bad sensor. I don't know if I got a dud, or it was a counterfeit? Amazon took it back either way so no matter.

I would be happy to run a Bosch 02 sensor - they invented them. Having said that I thought 05/06 had heated 02 sensors and 07+ switched to A/F sensors? Someone here told me I think?

 

[mtnbound]

I wondering if i have a bad sensor or what, it would be kinda coincidental.

had recurring p0420, due to cheap cat failing after ~10k miles. that resolved the p0420, then like a few days later the p1148 came up.

anyone had this happen?

 

[Lowcountry idn]

I wondering if i have a bad sensor or what, it would be kinda coincidental.

had recurring p0420, due to cheap cat failing after ~10k miles. that resolved the p0420, then like a few days later the p1148 came up.

anyone had this happen?

Try re-seating the connector?

Wouldn't be the first time I inadvertently damaged something taking it out and putting it back in. Could easily be the sensor?

 

[mtnbound]

Try re-seating the connector?

Wouldn't be the first time I inadvertently damaged something taking it out and putting it back in. Could easily be the sensor?

well, I never disconnected it, i just unscrewed it from the cat and screwed it back in. I just need to get out and look at it, the sensor could be loose, or maybe there is an exhaust leak at the flange going into the cat if possibly one of the bolts came loose or something.

or it could just be the that now that the cat is working properly, the system is able to detect that the o2 sensor is bad?

its the oem one i dont think i ever replaced this side, the driver side o2 failed shortly after replacing that cat too.

 

[Lowcountry idn]

well, I never disconnected it, i just unscrewed it from the cat and screwed it back in. I just need to get out and look at it, the sensor could be loose, or maybe there is an exhaust leak at the flange going into the cat if possibly one of the bolts came loose or something.

or it could just be the that now that the cat is working properly, the system is able to detect that the o2 sensor is bad?

its the oem one i dont think i ever replaced this side, the driver side o2 failed shortly after replacing that cat too.

p1148 is a Nissan Specific code that says the ECU isn't reading from the sensor or something similar. Can you monitor the actual sensor value - might tell you something?

 

[westslope]

.....Having said that I thought 05/06 had heated 02 sensors and 07+ switched to A/F sensors? Someone here told me I think?

My 2006 OR takes A/F ratio sensors up front. Or... perhaps the FSM along with several part store websites mislead me.

Just checked the 2005 FSM. A/F.

 

[Lowcountry idn]

My 2006 OR takes A/F ratio sensors up front. Or... perhaps the FSM along with several part store websites mislead me.

Just checked the 2005 FSM. A/F.

2005 / 2006 are a different Denso part number. I wonder what changed? Possibly just a different model or some minor thing.

 

[mtnbound]

p1148 is a Nissan Specific code that says the ECU isn't reading from the sensor or something similar. Can you monitor the actual sensor value - might tell you something?

View attachment 141928

It sounds like its not an exhaust leak, but mroe likely related to the sensor, wiring, or possibly a fuse.

thanks this was very helpful!

 

[DougGuy]

I guess I was barking up the wrong tree, I was thinking there is a problem with the sensors, so I was going to replace them thinking they would make the service engine light go off. The last time it was scanned with the light on, it was the P0430 or P0420 code, I forget which. Converters were new in 2/2020 and have 22k mi on them now. I ordered Bosal, but Rock Auto send Magnaflow primary converters, so I figure I might have come out ahead on that one, big difference in price from Bosal to Magnaflow, I just didn't want to have to replace them already, and the service engine light comes on and stays on for a week or two, then it goes off and stays off then it comes back on again.

I got lucky and got the required inspection done today so I can get my registration for 2022 while the light was off.

 

[JPH]

I have had no issues with the Denso O2 sensors for my ‘05. I replaced all 4 when I did it?