Looks like I mixed up the direction of the MAF harness. Pin 5 (black/yellow) DOES have 12V present. I was looking at pin one (green/yellow) by mistake.




Continuing on, I read 199 ohms with ignition off, and harness disconnected, between pin 3 (red/green) and body ground.


From there, it says to run a voltage test between ecm/pcm connector and body ground for 1.5V while engine holding at 2000 RPM


Where is the ECM/PCM connector? (connector C (22P))

 

See attached photos for ECM/PCM Connector C location and terminal pins no. 21 and 22.


At idle, you should see 1.1 - 1.6V at pin 22. You'll have to backprobe to check voltage there though.


Backprobing is either using a backprobe set or using a thin needle or something and making contact with the metal terminal of the connector without piercing the wire in the back of the still connected connector. Care must be taken to ensure that the wiring does not get damaged. You can use something like a T pin, available at Walmart, etc., and backprobe. These pictures are just to give a picture of the concept of backprobing without piercing any wires.

https://www.hondaaccordforum.com/foru...%5D-t-pins-jpg

https://www.hondaaccordforum.com/foru...back-probe-jpg

 

Thanks for the diagram. Will try that soon.


One other question: When I changed the MAF/IAT sensor, the problem got worse. Is that normal? I bought a cheap replacement, and it had finger prints all over it. I was thinking that I may have bought a bad part. I put the old one back in. Is there a way to test the sensor itself? Just to recap again, I was getting slight misfires that were not throwing codes, then I cleaned the sensor, but I think I didn't let it dry long enough. When I put it back in, all of the codes and ck engine appeared:


P0102 Mass or Volume AirFlow Low Input
P0113 Intake AirTemp Circuit High Input
P0300 Random Misfire
P0301 No. 1 Cylinder Misfire
P0302 No. 2 Cylinder Misfire
P0303 No. 3 Cylinder Misfire
P0304 No. 4 Cylinder Misfire

Maybe I should buy another sensor just to make sure?


Thanks for your help and guidance so far.