One common cause of a p0171 or p0174 code is a dirty Mass Airflow Sensor. This article with pictures is meant to assist Honda Accord owners in cleaning the MAF.
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The vehicle used in this article is a 2004 Honda Accord.
Tools and Materials:
- Philips Screwdriver
- Mass Airflow Sensor Cleaner
- Mass Airflow Sensor for Honda Accord (2002-2007)
- Mass Airflow Sensor Honda Accord (2008-2012)
How to Clean the Mass Air Flow Sensor on a Honda Accord
Start by popping the hood.
Locate the Mass Airflow Sensor near the Air Filter, this will be near the battery.
Press the plastic clip to release the connector, and pull it away from the MAF.
Use a Philips screwdriver to remove the 2 screws.
Carefully remove the MAF.
Locate the sensors, they almost look like little resistors. If they appear contaminated, spray them off with Mass Airflow Sensor Cleaner.
Be sure to check the ones on the bottom as well.
The ones in these photos appear pretty clean. If they appear contaminated with what looks like dust and soot, spray them with the cleaner.
Then let the MAF dry for a few minutes before re-inserting it into the slot.
Tighten the screws, and you are finished.
If the error codes persist, and you need to replace the MAF altogether, check out the link below for the part number.
Tools and Materials:
- Philips Screwdriver
- Mass Airflow Sensor Cleaner
- Mass Airflow Sensor for Honda Accord (2002-2007)
- Mass Airflow Sensor Honda Accord (2008-2012)
Practical Mechanic 
Interesting… Without the MAF, the car will operate in safe mode, meaning very rich mixture. With the MAF, it is trying to balance the mixture properly.
If you’ve tried a known good MAF,
then I would recommend you check for a vacuum leak.
This is my best guess at the problem.
You may have a hole or rip in the rubber intake elbow. Unmetered air is getting in between the MAF and throttle body. If you disconnect the MAF, it richens the mixture enough to run. Check the tube from the idle control valve into the elbow. These can easily tear, rip, or split.
That part you’re talking about is brand new, I forgot to mention I just did an engine swap on it and it’s happening. The year and model engine was put it.
Oh wow, nice work, sounds like an awesome project!
The only other thing that comes to mind is the hose from the pcv valve to the intake manifold – just double check that it is connected with no leaks.
Good luck!
Ok I will. I also changed out the pcv valve, thought that could be the issue. Thanks for all your help I really appreciate it. If I figure out the problem I’ll definitely tell you what it is
Sounds good, I hope you get it solved! Looking forward to hearing the solution…
Hi Ramzan,
The pin out goes like this:
A – Black – Low Reference
B – Tan – IAT Sensor Signal
C – Black. – Ground
D – Pink. – Ignition 1 Volt
E – Yellow – MAF Sensor Signal
Good luck! Hope it goes well!
Hey, thanks for you reply but I don’t have those color wires. I have green/yellow , red/yellow, red/green, black/red, and black/yellow
Okay, that helps to have the colors! For your sensor, the colors correspond to the following:
1 – green/yellow – Circuit Z28
2 – red/yellow – Sensor Output IAT
3 – red/green – Sensor Output VG+
4 – black/red – Sensor Ground VG-
5 – black/yellow – Fuse 18
Hope it’s helpful!
What exactly is that fuse 18?
Typical fuse, blows to protect the circuit if over-current. It’s located under the dash, I believe.
Thanks for your reply. I wired my Maf sensor in the color coding you gave me an the check engine light finally went away . Now when I start my car it shuts back down after 2 seconds. And I tried a brand new oem Maf sensor and same thing. I don’t have any check engine light now , the car just dies as soon as I start it. When I unplug the Maf sensor the car starts fine, I’m stuck, what else you think it could be ?
What are the color for diagram for the Maf sensor? Like which wire goes where on the connector, thanks