CEL Issue via MAF Sensor, Thoughts?

[The Architect]

Here's the quick and dirty.

About maybe...2 weeks ago my CEL would come on and go off randomly for periods of time, In the last week to a few days its been more frequent and now it seems to be on permanently. I used a code reader to narrow it down to the MAF Sensor.

I'm using the AFE Stage 2 Intake although I dont see how that could matter because Ive had it problem free for quite some time and even now with the CEL I don't really notice any real issues other than the fact that the light is on.

Not sure if I should bring it to a dealer seeing as how my yaris is heavily modified and they might nit pick.

Thoughts...

[changchewsoon]

Yup, a good mechanic should be able to tell you what is wrong, try asking him to clean the MAF first to see whether it helps. It could be some dirt/debris that is trapped or blocking the sensor.

Then, clear the error code in the ECU and drive it for a few days to see how it goes.

[m911gt]

my scan gauge indicated a similar problem a couple weeks back, i have the same intake. the problem happened after a really damp day and i had cleaned my engine bay that very same afternoon...i cleared the code the next day and it never came back. i assumed the MAF may have gotten moisture on it when i wiped the bay down.

[tk-421]

A dirty MAF sensor is a very likely culprit. I've read that cleaning can be accomplished using a compressed air can, but you need to be very gentle or you may damage it.

[White Yaris]

1+ to who said dirty MAF, damp weather, and loose MAF.

[The Architect]

Well I pulled the MAF out and came to see that it was merely a plastic piece with a small metal rod/ball tucked up inside it (I didnt know this) and it didnt look to be dirty but then again how would I know.

I have compressed air and calm hands should I need to clean it but how would I go about this. Is the metal piece highly sensitive to touch, is there anything i should or should not clean it with...etc....etc

Any and all advice is appreciated.

[YarisSedan]

Purchase a can of MAF cleaner and spray it liberally on the sensor wire. You should be able to see lots of dirt buildup. Specially with any type of cone filter if you dont clean them regularly dirt starts to bypass the filter and contaminate the sensor. Think of it as a sponge it can only hold so much water before it starts to leak. Same thing with your filter if you dont take it off and clean it regularly sooner or later dirt wont be trapped anymore. There are a few brands out there of MAF cleaner just go to your local auto parts store and ask for a can.

[CTScott]

The metal piece is the intake air temperature sensor. The actual MAF sensor is within the plastic. To clean it you gently blow out the "tunnels" in the plastic part.

CRC makes a MAF cleaner, which is specifically designed for cleaning them, but just blowing out the tunnels usually resolves intermittent issues.

[CTScott]

Actually, here's a good write-up on cleaning the Yaris one:

http://www.yarisclubuk.com/forum/viewtopic.php?t=131