Getting this code for about 6 months now (I know I know, better late than never!! ) and need to start digging in to solve. All maintenance done by Honda, 47000 miles. No other issues. Any thoughts? Thanks!!
Vacuum Leaks– With the Honda Pilot, one of the most common cause for the P0172 code to show is a vacuum leak. Take a look around and see if you can find the vacuum leak. Here’s a great YouTube video on how to find a vacuum leak.
Oxygen Sensor– The P0172 codes is thrown when the oxygen sensor(s) do not register the right amount of oxygen in the exhaust. When the oxygen sensor is bad, it can cause a false reading and trigger the code. The computer will still adjust the air/fuel mixture to compensate. This will cause the Pilot to run rich. Honda Pilot O2 Sensor
Mass Air Flow Sensor– The mass air flow sensor calculates the volume of air entering the engine. If it has gone bad, the air fuel mixture will be off and the P0172 code will show.
Bad Fuel Injectors– If you have one or more fuel injectors that have gone bad that can certainly cause the air/fuel mixture to go bad.
Fuel Pump/Fuel Filter– Today’s modern fuel injected motors need a lot of fuel pressure to atomize the gas properly. If the fuel pressure is off, atomization doesn’t happen properly and the optimal air/fuel mixture isn’t achieved.
Air Filter– While it’s not the most common reason to throw the P0172 code, a clogged air filter certainly can cause the code to throw. And, since it’s so easy to check, why not look?
I'm willing to bet its tied in with the injectors. P0172 is not one of the official code thrown for the TSB 19-072 and 19-073 on the Pilot. However, on the Accord found this: 'The P0172 code on a Honda Accord will often be thrown if the fuel injection system is not operating properly. Typically the code will be triggered by a rich condition in the engine.'
You might want to get a dealer to check it out. They may be able to pull more information than a generic scanner can find. And if it is the injectors, you might be able to get Honda to cover some of the cost.