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Weird discovery of po171 code and MAF SENSOR

821 Views 6 Replies 3 Participants Last post by  Skidoo5064
So if u look at my last post about my po171 code problem u will understand this post.. so today I took out the Bosch o2 sensor I put in last month with original Gm acdelos. Now my fuel trim numbers were high especially my long tirm fuel trim. Now I went and looked a my MAF sensor reading and it was reading .20 to .30 lb/gram. (Whatever the name is) when it should be between 1.00 To 2.00… so I noticed it was low. Now I just replaced that sensor last month as well. It’s brand new.. but it’s a duralast brand… could the sensor gone bad? When it was brand new it would read 1.00 to 2.00 now could it have gone bad bc of the bad turbo that was just taken off and replaced? And also here’s the best part that gets crazy. WHEN I UNPLUG MY MAF SENSOR. My fuel trim numbers start to drop and go to the numbers that it’s supposed to be!!! That’s crazy. Also my fan will kick on and stay on for a bit but ends up turning off.. but my fuel trim numbers start to read what they should be. I then plug it back in and tho my fuel trim number continue to read good and stay good as I drive. Also the po171 code doesn’t kick on… but the MAF sensor numbers continue to read low numbers at idle. Also once I turn off the car and turn it back on. My fuel trim numbers go back to high numbers( basically running lean and going to get the po171 code again until I unplug the MAF SENSOR again… what is going on? Is it a bad MAFsensor bc it’s duralast? Or is the power train controls module faulty??? Ideas???
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· The Nuclear Option
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5,881 Posts
So if u look at my last post about my po171 code problem u will understand this post.. so today I took out the Bosch o2 sensor I put in last month with original Gm acdelos. Now my fuel trim numbers were high especially my long tirm fuel trim. Now I went and looked a my MAF sensor reading and it was reading .20 to .30 lb/gram. (Whatever the name is) when it should be between 1.00 To 2.00… so I noticed it was low. Now I just replaced that sensor last month as well. It’s brand new.. but it’s a duralast brand… could the sensor gone bad? When it was brand new it would read 1.00 to 2.00 now could it have gone bad bc of the bad turbo that was just taken off and replaced? And also here’s the best part that gets crazy. WHEN I UNPLUG MY MAF SENSOR. My fuel trim numbers start to drop and go to the numbers that it’s supposed to be!!! That’s crazy. Also my fan will kick on and stay on for a bit but ends up turning off.. but my fuel trim numbers start to read what they should be. I then plug it back in and tho my fuel trim number continue to read good and stay good as I drive. Also the po171 code doesn’t kick on… but the MAF sensor numbers continue to read low numbers at idle. Also once I turn off the car and turn it back on. My fuel trim numbers go back to high numbers( basically running lean and going to get the po171 code again until I unplug the MAF SENSOR again… what is going on? Is it a bad MAFsensor bc it’s duralast? Or is the power train controls module faulty??? Ideas???
What's going on when you unplug the MAF sensor the ECM reverts to using speed density to select the fueling and commands open loop which ignores the oxygen sensors for the remainder of the cycle.

I only use GM sensors, most aftermarket sensors have a horrible reliability track record based on my experiences.

With every plugged in, What are the LTFT'S in gear at operating temperature at idle and what are they under boost?
 

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2015 Cruze 1.4L engine 6 speed AT
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1,246 Posts
It’s brand new.. but it’s a duralast brand
Well, you aren't the first person to have the same problem. Sadly it happens constantly, just words of wisdom for the future. Every sensor or part that controls the engine needs to OEM.

I lifted this from the autozone website.

★★★★★★★★★★1 out of 5 stars.
· 5 months ago
Did not work
The part didn’t work and they refused to refund my money.
  • What kind of vehicle do you drive?
  • 2013 Chevy Cruze lt

Recommends this product
✘ No

I also made an interesting observation, the old reviews fall of the website. Otherwise there would be a flood of bad reviews.:censored:
 

· Registered
Joined
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10 Posts
Discussion Starter · #6 ·
Well, you aren't the first person to have the same problem. Sadly it happens constantly, just words of wisdom for the future. Every sensor or part that controls the engine needs to OEM.

I lifted this from the autozone website.

★★★★★★★★★★1 out of 5 stars.
· 5 months ago
Did not work
The part didn’t work and they refused to refund my money.
  • What kind of vehicle do you drive?
  • 2013 Chevy Cruze lt

Recommends this product
✘ No

I also made an interesting observation, the old reviews fall of the website. Otherwise there would be a flood of bad reviews.:censored:
Well, you aren't the first person to have the same problem. Sadly it happens constantly, just words of wisdom for the future. Every sensor or part that controls the engine needs to OEM.

I lifted this from the autozone website.

★★★★★★★★★★1 out of 5 stars.
· 5 months ago
Did not work
The part didn’t work and they refused to refund my money.
  • What kind of vehicle do you drive?
  • 2013 Chevy Cruze lt

Recommends this product
✘ No

I also made an interesting observation, the old reviews fall of the website. Otherwise there would be a flood of bad reviews.:censored:
I have an appointment with a used car dealership where I got this from to check and see if it’s the sensor being faulty if it is I’m gonna have them get me an AC Delco one but other than that I don’t know what it could be if it’s a short in my wire harness or if it’s the powertrain module
 

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10 Posts
Discussion Starter · #7 ·
What's going on when you unplug the MAF sensor the ECM reverts to using speed density to select the fueling and commands open loop which ignores the oxygen sensors for the remainder of the cycle.

I only use GM sensors, most aftermarket sensors have a horrible reliability track record based on my experiences.

With every plugged in, What are the LTFT'S in gear at operating temperature at idle and what are they under boost?
I don’t know what the fuel trim numbers are under boost but when it’s a idol and I don’t unplug anything my short term field trim stays at like -2 to 5 and my long-term field trim stays at 34 also I have smoked this thing a few times and there’s no air leaks I do know my air filter is a little dirty but I don’t think that’s the main problem
 
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