nuke1105

The check engine light came on after i pressure washed my 2002 tacoma prerunner engine. The local mechanic said its giving out the code for the MAF Sensor. He said it probably just need to be cleaned. How do i know if its bad or just needs to be cleaned? I washed the engine, drove around about an hour then parked my truck. The following day the check engine light came on. The light remained on for 2-3 days then it randomly turned itself off for a day. Now its back on. Seems like in the last 2 weeks its been on and off without me doing anything to reset the light. What do you guys suggest? I read somewhere that i should clean the MAF with electronic parts cleaner? What do you guys recommend? Thanks!!

MillerPKA

What you said last is right. Pull your maf sensor housing out and hit the sensor with the electronics can while avoiding to pummel it with air. Pull your ecu fuse (engine bay box) during the cleaning and plug it back it when you're done, take a drive around and see if stays off. If not then its off to get another one

DailyDrive

Think about it. You pressure washed your engine, and your MAF got dirty, so it needs cleaning. Does that make sense? It does not.

You likely got water in some electrical connections. Pressure washing anything on the vehicles is a pretty crazy idea, especially the engine, as most things are designed to withstand splashes of water coming from above, like in the case of rain. High pressure water will get into places that were designed to stay dry in normal wet conditions.

nuke1105

So it does make sense to me but..............if the sensor got damaged why would the check engine light turn itself off for a day and back on the next? I understand pressure washing the engine was not smart but I did it already and the damage is there. Now I need to solve the problem. When the truck was hooked up to the OBD machine it gave off an error code related to the MAF. So that would mean that my problem is the sensor?or could it be another problem?

DailyDrive

The sensor is inside the intake tube, which is air tight, and therefore water tight also. There is no way water could have gotten to the sensor itself, and certainly water did not get it "dirty" to warrant a cleaning.

Light going on and off, and any other intermittent problems sounds like there is water in the electrical connections somewhere. You can just wait until it dries itself. Could take more than a week. Or start cleaning all electrical connections with a blast of compressed air.

nuke1105

Good advice. I will remove the ecu fuse. Then will begin to air dry all electrical connections I see. If the light comes back on I will pull the exact code and go from there even though the mechanic said it was the MAF.

DailyDrive

Start with drying the electrical connector going to the MAF.

nuke1105

Ecu fuse? Is that the fuse in the engine compartment labeled PWR Outlet?

MillerPKA

No its the one labeled ecu

nuke1105

No ecu fuse in the engine compart. But I did find one in the dash. It's labeled ecu-ig and ecu-b. I pulled them both. Took the MAF out and wow!!! That thing had dirt on it!!! The plug the connects to the MAF was wet also. I'm drying the plug and allowing the maf to dry in front of my fan. Hopefully this will work!!

MillerPKA

ah i messed up abbreviations, plug your ecu fuses back in, go back to the hood box and unplug efi. sorry it was a long night

nuke1105

How do I leave it unpluged for

MillerPKA

15 min should reset it, it takes days, sometimes weeks, for the efi to fully readjust but itll be fine, if the cel's gone at the end then you'll be golden

eddieleephd

Use Di electric to seal the plug and no water will effect it. just use liberally so that the plug is pretty much full and nothing esle can get in.

nuke1105

okay guys so i cleaned the little bulb on the MAF, cleaned the little tunnel where the two wires are in the maf and let the unit fan dry on low speed for about 10 minutes. I used electronic parts cleaner from radio shack. I got my wifes hair dryer and dried up the plug that connects to the maf cause it was still wet even after 2 weeks!!! I removed the efi fuse for about 10 minutes and the check engine light is still on :-( So im going down to the auto parts store to get the code pulled again and have them delete the code. Im going to drive around and see if that fixes the problem. Ill keep ya posted. This really sucks cause that maf cost 200 bucks. I could of got my whole truck detailed for that much money!! (Not to happy right now)

MillerPKA

used maf from a yard

nuke1105

Went to the auto parts store and got the code cleared. Before he cleared it it came up as p0171 i think. Which pretty much is the lean error code for the maf. Anyhow i drove the truck 40 miles in 40-50 minutes and the check engine light hasnt come back on. Hopefully the cleaning I gave the maf will have worked.

eddieleephd

This code is usually thrown when you have a dirty maf because the sensor is sensing less o2 so the ecm delivers less gas, hence lean code.

nuke1105

so cleaning the maf didnt work. The check engine light came back on. Im going to buy a new sensor from auto zone. they are 69.99 with core exchange or i can go dealer for 212 plus tax. Both have 1 year warranty. Thanks for all the help guys.

eddieleephd

check the code first it may actually be the o2 sensor that is part of the issue with a lean code.