p0131 p0171 p1101 Codes.

[JerryMah]

Had the check engine light come on in my 2015 Encore with 151000km. p0131 p0171 p1101 codes came up on the code reader. Looks like the valve cover has a vacuum leak so that has to be replaced however do I need to get the intake manifold replaced also?
I read they are related repairs.
Looks like the non return valve is also missing in the intake manifold.

 

[Again]

You will hear the hissing from the front of the regulator and covering it with your finger will stop it if it's the valve cover. Then you will have to change it.

As for the Intake manifold PCV if you can see it you don't need to touch it. It is bright orange silicone rubber and you can see it with a flashlight, it's inside the intake about 4" down to the right when standing in front. Took this picture with my endoscope. You can't miss it. If you see the orange nib the valve is still there.

But if you ask me....

DTC P0131 HO2S Circuit Low Voltage Sensor 1
DTC P0171 Fuel Trim System Lean
DTC P1101 Intake Air Flow System Performance

These codes lean more towards a dirty air filter. When is the last time you checked it or changed it. Sometimes moles or squirrels will nest in the air box causing these exact codes. Not enough air getting to the throttle body.

 

[JerryMah]

You will hear the hissing from the front of the regulator and covering it with your finger will stop it if it's the valve cover. Then you will have to change it.

As for the Intake manifold PCV if you can see it you don't need to touch it. It is bright orange silicone rubber and you can see it with a flashlight, it's inside the intake about 4" down to the right when standing in front. Took this picture with my endoscope. You can't miss it. If you see the orange nib the valve is still there.

But if you ask me....

DTC P0131 HO2S Circuit Low Voltage Sensor 1
DTC P0171 Fuel Trim System Lean
DTC P1101 Intake Air Flow System Performance

These codes lean more towards a dirty air filter. When is the last time you checked it or changed it. Sometimes moles or squirrels will nest in the air box causing these exact codes. Not enough air getting to the throttle body.

Changed air filter in March. I was going to change the valve cover but now I’m taking it to the dealer on Tuesday to see if the intake manifold needs to be changed also.

 

[Again]

Changed air filter in March. I was going to change the valve cover but now I’m taking it to the dealer on Tuesday to see if the intake manifold needs to be changed also.

Did you check the filter box?

 

[JerryMah]

Did you check the filter box?

Yes. Everything looks fine.

 

[Buickman99]

Yes! I Have a 1999 Buick Lesabre . It is a great car and love it. I have a code that has came up . P0171 I have replace both O2 Sensors. So I that would help. But It didn't . So I had the Catalytic Converter replaced. So I that would help . But the same code up. Can any One help me with this.
She is a great car . It was handed down be by my Father In-Law. Can any body give ay suggestions please ?

 

[Again]

This is the Encore forum. Maybe you'd have better luck in the "Past Model" forum...

 

[JerryMah]

Well I opened the hood and there was oil everywhere. The tech thought there was a crack in piston. After further inspection the pvc valve was damaged due to excessive crankcase pressure. Turns out the pcv port was carboned over causing high pressure. Both the valve cover and the intake manifold had to be replaced again. So if anyone has a blown valve cover there could be a lot more to repair than the cover.

 

[Hdw]

I have a 2017. Started throwing codes, 1101 and 0171 among them. Replaced the valve gasket cover, intake manifold and PCV valve. Rough idle seems to be better, but still getting same codes. Buick diagnostic says emissions system, and my Stabilitrak light comes on intermittently. I also have a very strong fuel smell outside the vehicle when it idles.
Any suggestions???

 

[Again]

Did you clean the MAF, it is probably running rich then lean to try and correct the issue. If it runs rich you will smell gas. I just had the same codes in my daughters Cobalt, I just replaced the MAF since it has high kilometers. Works fine now.

P0171 will turn "OFF" Stabilitrak like a lot of other engine codes, P03** for example.

 

[Coppy]

I have a 2017. Started throwing codes, 1101 and 0171 among them. Replaced the valve gasket cover, intake manifold and PCV valve. Rough idle seems to be better, but still getting same codes. Buick diagnostic says emissions system, and my Stabilitrak light comes on intermittently. I also have a very strong fuel smell outside the vehicle when it idles.
Any suggestions???

I have had the same problem with my 2017 Encore. Is this an issue with these vehicles? I like the Encore and would consider buying another but have had 4 things fail on it in the last year.

 

[Markstack]

I have a 2019 Encore with 47k kilometers. Driven occasionally. Had P0101 (Mass Airflow Sensor), p0172 (Fuel Trim Rich), P1101 (Intake Air System Performance) last July 2025, all at once. Took to dealer. Dealer replaced MAF sensor ($262.82 CDN), genuine GM part, in July 2025.
P1101 has come back in August, one month later, car is almost undriveable. I suspect the MAF was okay and there is an air leak somewhere, or the PCV valve is faulty. Not sure. I will take a look and let this board know.

 

[DocBrown]

PCV. Which engine, LE2 or LUV? The LUV is the more expensive one to replace the PCV because it's built into the valve cover.

 

[Markstack]

It is the Turbo model. Which model is that? LE2 OR LEV?

 

[mshultz]

LE2 is the direct injection engine. This is my 2019 Encore direct injection engine. Note the insulated pipe that runs across the engine cover, and the AGM battery.

 

[Markstack]

LE2 is the direct injection engine. This is my 2019 Encore direct injection engine. Note the insulated pipe that runs across the engine cover, and the AGM battery.

Okay, thanks for the pic. Mine is like that as well. So, no turbo.

 

[mshultz]

Actually, both engines have turbos. The 2019 Buick Encore brochure describes the standard engine (LUV) as "1.4L Turbo Engine with Variable Valve Timing (VVT) and DOHC."
The optional engine (LE2) is described as "1.4L Turbo Engine with VVT, SIDI and Stop/Start Technology."

 

[G-29663]

Very helpful, thanks. I apparently have the LE2 (with the turbo). I have rarely looked under the hood, but I suspect I will be spending some time doing so.

 

[DocBrown]

Look at the 8th digit of your VIN. The LE2 engine code is "M", the LUV engine code is "B". Both engines are 1.4 l and both have turbo chargers.

The LE2 has 3 PCV valves. They are all easy to get at. I had a shop do mine and it was about $200. One was completely plugged. The parts are about $60.

 

[Markstack]

Look at the 8th digit of your VIN. The LE2 engine code is "M", the LUV engine code is "B". Both engines are 1.4 l and both have turbo chargers.

The LE2 has 3 PCV valves. They are all easy to get at. I had a shop do mine and it was about $200. One was completely plugged. The parts are about $60.

Thanks for the info. I have an "M" meaning LE2. That circuitous routing of that insulated pipe is something to behold. I put my car up on a lift and found that a portion of the tube (rubber in this case) rubs against an electrical connection and there appers to be a hole worn into the rubber tube. See picture. I suppose this could be a cause of the check-engine light. Today the engine light is off, but the code reader still reads the two codes: P1101 and P0172 (fuel trim). Going to take the car back to dealer. I don't think they did a smoke test the first time. They just changed the MAF, which is clearly not the issue. The more I learn about the 1.4 Ecotech, the less I am impressed. All part of the fun 🙂