Dear Veterans

Need help on P0171.

I had the following error codes
1) P00662-00 Intake manifold tuning valve control - circuit high - bank 1 Intermittent
2) P00661-00 Intake manifold tuning valve control - circuit low- bank 1 Intermittent
3) P0171-00 System too lean (bank 1) Intermittent.

Replaced the intake manifold tuning valve and got rid of the the first two error codes. Initially thought the third code is also related to the valve, but it came back again. Please suggest the possible causes for P0171. I also noticed increased levels of CO2 inside the cabin, especially at traffic lights, not sure whether this is related to this problem.

 

Engine type would help;

 

I had some similar issues and I had cracks in the vacuum lines along the passenger side of the engine by the supercharger.

 

3.0 V6 Supercharge Petrol Engine

 

Thank you for the input. Couldn't find any crack. Felt some oil residue along this hose. Could there be a leak at the circled connector?

 

his engine details are in his signature Kansan 3.0 v6 2012

 

Thanks.

 

What do you mean by this ? CO2 ? CO ? Smell ?

 

From the Jag manual

 

I felt some faint smell and used an air quality tester and found the CO2 levels shooting up.

 

Hope the attached videos are accessible.

 

push them together while the car is running and you should notice, that or do a smoke test or spray carb cleaner in the area, if the engine surges then there is a leak there.

on my 5.0L supercharged it was hidden along the passenger side of the engine among about 6 other hoses, it was a pretty obvious crack in one of the hard plastic bends.

 

No luck in finding any crack. Have ordered the PCV valve. Will update after replacing it.

 

First CO2 has nothing to do with your problem?? You emit CO2 continuously so your the most likely source.

If your trying to find cracks in the plastic piping you need to get the car running at idle and display the fuel trims in real time. Next you start spraying carb. cleaner around the tubes or area's you think might have a leak while watching the fuel trims. It can be a tedious job and don't forget there are a lot of potential leak spots!

Now since you only have a lean code on one bank we can eliminate holes in the intake ducting. This is a real common failure as the years go by and the plastic gets more brittle. But that is a shared part and will set lean codes on both banks of cylinders. So make sure you know which bank is bank one and concentrate on that side as the codes point to that area.
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Update!!

Finally, the error code disappeared.

Replaced the PCV valve with no resolution.

The local garage guy suggested trying a DPF Cleaner. He removed the oxygen sensors and cleaned them and sprayed a bottle of DPF cleaner inside the CAT filter on each side. I drove the car for a couple of days and checked again, the error code is not there.

Thank you all for your inputs.