NEED HELP P1174 With CEL

$ Khalid ! 9130

Well-Known Member
Hey everyone

Was out driving today, CEL comes on

I think it's for the misfire in cylinder 3, so when i was stopped, checked the code and it turned out to be a P1174. I noticed the TB was driving a bit weird as well. Checked online and it turns out it could be a number of issues, mostly to do with the fuel injection system.

Anyone else have had this code and where should i start?

Thanks
 

C-ya

Well-Known Member
My wife's Impala (2004, 3.8) just had a MAF code P0103 and the P1174 code. I read online that if the MAF is bad or not at 100%, the engine can run lean since it doesn't know how much air is actually coming in. On looking at the MAFs output, the frequency was changing, but apparently it was out of spec. I tried cleaning the MAF but the codes kept coming back so I replaced it. Once the new MAF was in, it ran so smooth! I also cleaned the throttle body plate as it was sticking after sitting.
 

rizzo20

Well-Known Member
Hey everyone

Was out driving today, CEL comes on

I think it's for the misfire in cylinder 3, so when i was stopped, checked the code and it turned out to be a P1174. I noticed the TB was driving a bit weird as well. Checked online and it turns out it could be a number of issues, mostly to do with the fuel injection system.

Anyone else have had this code and where should i start?

Thanks
I have been fighting a P1174 for several months now in my SLE and have yet to get rid of it. Most of my research and advice has pointed toward a vacuum leak or clogged fuel injector. Things to check are loose intake manifold bolts, cracked or split vacuum lines, and run fuel injector cleaner through the tank.

I tightened up my intake bolts which were pretty loose, ran fuel injector cleaner through the tank, purchased professional fuel injector cleaner kit that runs the vehicle solely on a cleaning mixture direct to the fuel rail and none of this has fixed the problem.

I stumbled on to a post somewhere here about a bad MAF sensor causing a false lean condition. Most of the troubleshooting is done by monitoring Short Term Fuel Trim Readings. Basically, by disconnecting the MAFS you will end up with two more codes related to having the MAFS unplugged but you may notice that the P1174 doesn't come back. Thats where I'm at right now. I drove a few hundred miles with the MAF unplugged and no more P1174, so I bought a can of MAF cleaner (don't try to use anything else) and cleaned mine but after plugging it back in the P1174 came back within 20 miles of driving. So I ordered a new MAFS. We'll see what happens next.

If I were you I would start with the in-tank FI cleaner, check intake bolts and a check for possible vacuum line leak as that is the cheapest route to get started on fixing it. I'll see if I can find a link to that thread I am referring to.
 

djthumper

Administrator

C-ya

Well-Known Member
@$ Khalid ! 9130 , MAF/MAFS = Mass AirFlow Sensor. Sorry!

As pictured above, it will be in the intake path between the air filter and the throttle body. There may (should?) also be an Inlet Air Temp (IAT) sensor in that path as well. On some vehicles, it is part of the MAF, like my niece's '06 Pontiac Torrent with a 3.4L V6.
 
OP
OP
$ Khalid ! 9130

$ Khalid ! 9130

Well-Known Member
The MAF is in the intake tube. The O2 Sensor is in the exhaust system.
That is what i thought! The reason i asked was when i read about the code online it said Oxygen sensor maybe bad...

Thanks :2thumbsup:

It should be on the piping coming from the airbox.View attachment 81247
The diagram is much appreciated :thankyou:

@$ Khalid ! 9130 , MAF/MAFS = Mass AirFlow Sensor. Sorry!

As pictured above, it will be in the intake path between the air filter and the throttle body. There may (should?) also be an Inlet Air Temp (IAT) sensor in that path as well. On some vehicles, it is part of the MAF, like my niece's '06 Pontiac Torrent with a 3.4L V6.
:2thumbsup:

Also is it advised to still drive the Trailblazer with this code, or would it create more problems if I do?

Once again a BIG Thank You to all of you for the help :grouphug:
 

Mooseman

Moderator
It could cause issues with your cat if it's running rich but it doesn't seem to be the case. Unplugging the MAF will revert it to pre-programmed values to run on according to other sensors (MAP, oxygen, throttle, etc.). As mentioned, you will get other codes for the MAF but clear them all and drive it to see if the P1174 goes away.
 
OP
OP
$ Khalid ! 9130

$ Khalid ! 9130

Well-Known Member
It could cause issues with your cat if it's running rich but it doesn't seem to be the case. Unplugging the MAF will revert it to pre-programmed values to run on according to other sensors (MAP, oxygen, throttle, etc.). As mentioned, you will get other codes for the MAF but clear them all and drive it to see if the P1174 goes away.
Will do, Thanks
 

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