04-13-2015, 02:25 PM
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How you got codes PO171+PO174? Find out what others did to solve the problem.
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Here’s a helpful hint to solve your issue Click Here
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Check Engine Codes: PO171+PO174 System Bank? What do they mean?
#76
02-02-2009, 12:50 PM
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Bobby,
I passed my emissions test. I cleaned MAF, throttle body, IAC, yada, yada, yada, and replaced a couple of vacuum lines. That didn't help at all. The CEL came right back on. I took it to the local mechanic and he got it to pass. He says he replaced the fuel filter, reset "the specs," drove it around (maybe 20 miles), and he got it to pass. He didn't do the test himself, either. The light is still off, too!
So, I don't know what actually happened, but I noticed the paperwork says that the type of test is "after repair." I would suggest finding a local guy who might be able to help with the test (more than fixing the CEL). My truck runs exactly the same right now. This rule in GA seems absurd to me now.
I passed my emissions test. I cleaned MAF, throttle body, IAC, yada, yada, yada, and replaced a couple of vacuum lines. That didn't help at all. The CEL came right back on. I took it to the local mechanic and he got it to pass. He says he replaced the fuel filter, reset "the specs," drove it around (maybe 20 miles), and he got it to pass. He didn't do the test himself, either. The light is still off, too!
So, I don't know what actually happened, but I noticed the paperwork says that the type of test is "after repair." I would suggest finding a local guy who might be able to help with the test (more than fixing the CEL). My truck runs exactly the same right now. This rule in GA seems absurd to me now.
#77
02-02-2009, 05:08 PM
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You had the MAF tested and it was deemed worthy of replacement or is this a money tossing venture?
You can reset the ECU by pulling the ECM fuse in the underhood fuse box. Easy enough.
For future reference, you can release fuel pressure by pulling the fuel pump relay (in that same underhood box) and cranking the engine dry for a few seconds.
Also, looking at whatever you want to will not substitute for an actual fuel pressure gauge and fuel pressure test.
Some of these F-truck exhaust manifolds are known to leak, so I would investigate that further. But, that is one heck of a leak on both banks.
You can reset the ECU by pulling the ECM fuse in the underhood fuse box. Easy enough.
For future reference, you can release fuel pressure by pulling the fuel pump relay (in that same underhood box) and cranking the engine dry for a few seconds.
Also, looking at whatever you want to will not substitute for an actual fuel pressure gauge and fuel pressure test.
Some of these F-truck exhaust manifolds are known to leak, so I would investigate that further. But, that is one heck of a leak on both banks.
Removing the small twist cap and pushing the button seems to work the best on releaving the fuel pressure imo. How can i get the maf sensor tested?
#78
02-09-2009, 07:44 AM
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#79
02-20-2009, 04:37 PM
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Yesterday on my way home from work....light came back on (131 miles) So yeah! I passed but boo this is still going on.
#81
06-19-2009, 02:26 PM
CEL light back on
I was able to pass smog (test only, CA). While driving home after the test, my Cel came back on.
I use the Truck as my Tow Vehicle and I definitely have loss of power/incorrect shift point. I'm going up the mountain in 2 weeks and need this resolved.
I finally give up.
Does anyone know a good mechanic in the Orange/Chino Hils California area.
Thx for the help...
I use the Truck as my Tow Vehicle and I definitely have loss of power/incorrect shift point. I'm going up the mountain in 2 weeks and need this resolved.
I finally give up.
Does anyone know a good mechanic in the Orange/Chino Hils California area.
Thx for the help...
Last edited by andymaan; 06-19-2009 at 02:30 PM.
#82
06-19-2009, 02:59 PM
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I was able to pass smog (test only, CA). While driving home after the test, my Cel came back on.
I use the Truck as my Tow Vehicle and I definitely have loss of power/incorrect shift point. I'm going up the mountain in 2 weeks and need this resolved.
I finally give up.
Does anyone know a good mechanic in the Orange/Chino Hils California area.
Thx for the help...
I use the Truck as my Tow Vehicle and I definitely have loss of power/incorrect shift point. I'm going up the mountain in 2 weeks and need this resolved.
I finally give up.
Does anyone know a good mechanic in the Orange/Chino Hils California area.
Thx for the help...
#83
06-19-2009, 04:10 PM
Hey guys,
I too have been bitten by the 171 and 174 bug. I have replaced the following:
- pcv valve (passanger side valve cover)
- both pcv elbows (pcv valve and on the back of the throtle body)
-cleaned the MAF sesor
-sprayed brake cleaner on the intake, pcv valve seal, and Throttle Body (no increase in idle).
* I have cleared the code (w/reader) multiple times but they return. I was actually able to smog the truck today after 90 miles. On the way home the CEL came on.
-I have also noticed a lack of power (or wrong shift points) when towing up hill.
-When I turn the truck off, I hear a hissing sound under the hood. Not sure where it's coming from, maybe by the radiator area (normal?).
I would love to stop these codes and get the truck towing properly again.
Thanks in advance,
Andymaan
I too have been bitten by the 171 and 174 bug. I have replaced the following:
- pcv valve (passanger side valve cover)
- both pcv elbows (pcv valve and on the back of the throtle body)
-cleaned the MAF sesor
-sprayed brake cleaner on the intake, pcv valve seal, and Throttle Body (no increase in idle).
* I have cleared the code (w/reader) multiple times but they return. I was actually able to smog the truck today after 90 miles. On the way home the CEL came on.
-I have also noticed a lack of power (or wrong shift points) when towing up hill.
-When I turn the truck off, I hear a hissing sound under the hood. Not sure where it's coming from, maybe by the radiator area (normal?).
I would love to stop these codes and get the truck towing properly again.
Thanks in advance,
Andymaan
thx for the help!
#84
12-28-2009, 10:50 AM
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I'm thinking I have the month of January to get this truck to pass again. I suppose I will try the same routine as last year:
1) clean MAF, throttle body, IAC, yada, yada, yada,
2) replace a couple of vacuum lines
3) replace fuel filter
4) reset the computer
5) cross my fingers and hope!
#85
03-10-2010, 12:34 PM
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Well just like everyone else I'm back to where i started....
Last year i replaced the Fuel Filter waited for 50 miles and got the test and passed. 2 days later the light came back on. So Now i'm working on the issue again. My Tag expired in January and well it's March so lets just say i'm getting gas alot more when i see a cop.. (THANK YOU GEORGIA).
So hoping that the Fuel Filter would help me pass again this year i made it 42 Miles and then comes on the Light. *BANG FIST ON TRUCK PANEL*.
So thinking that I have done everything I could i replaced the MAF. Reset the battery and the light came back on.
So now i'm sitting here worried about every trip i make and about my truck not being able to pass this 25$ test so i can get my tag.
I'm just going to hope that I can remove the battery plugs again and hope i can make it, from the sounds of it after 20 miles ill be going in this time to see if it can pass.
Last year i replaced the Fuel Filter waited for 50 miles and got the test and passed. 2 days later the light came back on. So Now i'm working on the issue again. My Tag expired in January and well it's March so lets just say i'm getting gas alot more when i see a cop.. (THANK YOU GEORGIA).
So hoping that the Fuel Filter would help me pass again this year i made it 42 Miles and then comes on the Light. *BANG FIST ON TRUCK PANEL*.
So thinking that I have done everything I could i replaced the MAF. Reset the battery and the light came back on.
So now i'm sitting here worried about every trip i make and about my truck not being able to pass this 25$ test so i can get my tag.
I'm just going to hope that I can remove the battery plugs again and hope i can make it, from the sounds of it after 20 miles ill be going in this time to see if it can pass.
#86
03-10-2010, 06:05 PM
From what I read here, -no one is checking everything. These codes are easy to trouble shoot.
However, your unlikley to receive good help without posting EVERYTHING you've done in order to solve the problem. Otherwise, it seems you really don't care enough about the problem to begin with, so why even try to help ?
However, your unlikley to receive good help without posting EVERYTHING you've done in order to solve the problem. Otherwise, it seems you really don't care enough about the problem to begin with, so why even try to help ?
#87
06-21-2010, 04:39 PM
Caved and took the Truck to the "Dealer"
Hey guys,
After trying each solution listed, I was unable to stop my CEL from returning. More important is the loss of power during towing. As soon as I get a diagnosis from the Dealer, I will keep everyone posted. Hopefully this will add to the solutions that are proven to resolve the code issues.
After trying each solution listed, I was unable to stop my CEL from returning. More important is the loss of power during towing. As soon as I get a diagnosis from the Dealer, I will keep everyone posted. Hopefully this will add to the solutions that are proven to resolve the code issues.
#88
07-07-2010, 12:12 PM
Resolved!!!! (PO171 and PO174)
My problems are resolved 
,
Just got back from a 500 mile towing trip with my truck. Tons of power for the mountain roads and still no CEL.
The fix:
The dealership replaced my Mass Airflow Sensor (I had cleaned it twice) and the DPFE sensor.
In my case the elbow, pvc valve, etc... had no effect.
Hope this helps,
Andymaan
,Just got back from a 500 mile towing trip with my truck. Tons of power for the mountain roads and still no CEL.
The fix:
The dealership replaced my Mass Airflow Sensor (I had cleaned it twice) and the DPFE sensor.
In my case the elbow, pvc valve, etc... had no effect.
Hope this helps,
Andymaan
#89
09-21-2010, 12:02 PM
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#90
11-06-2010, 05:56 PM
