Check engine light

Hello all, new member with a 2004 Tacoma 4x4, AT, 2.7 4 cyl engine. Check engine light on, ran the code and it says mass air flow sensor. Replaced with one from auto zone ( duralast brand ) twice. Code comes up again, P0171. This has been an issue for about two weeks. Does anyone have an idea what I should do next? Love my Toyotas, but this one has me scratching my head...

 

Dear Black Top,

Describe what the code P0171 means for those of us who don't have the error codes memorized. Is P0141 just the mass air flow sensor, or does it have something to do with the air intake into the throttle body? Did you replace your air filter at the same time you replaced your mass air flow sensor? I would clean out the entire air intake system including the throttle body and the idle air control valve, and see what happens then. It does seem highly unlikely that it is the mass air flow sensor since you replaced it twice. The only thing I could possibly think of is that may be there is a difference between a Toyota one and an Auto Zone one.

Good Luck,
Paul

 

http://parts.olathetoyota.com/p0171-code-toyota

There's extremely good info here ^^^^

 

Does the CEL come on instantly or after a drive? If instant I would look for wire damage... maybe critters...

 

Check the rubber intake boot for any cracks. Spray carb clean around the intake tube and around throttle body listening for the engine rpm to change. If it does you have a leak after the mass air which the ecu hasn't accounted for causing the code to set.

 

Thanks to those who shared their suggestions on how to fix my problem with mass air flow code coming up. I plan to test for cracks in the induction tubes first, and then try a Toyota mass air flow meter if necessary. Again, grateful for the input....

 

Tacomajunkie86, code PO 171 translates to mass air flow meter.

 

p0171code is usually set by dirty MAF, but have seen poor quality gas cause these codes. E-85 will cause this code in a heartbeat. Clean the maf, then pull the efi fuse for a minute to re-set fuel trim memory.

 

^ he is right. The code is stored for a lean condition. It's possible to have bad gas but usually not always your will have misfire conditions as well or sputter with bad gas. My bet is you have a small vac leak after the mass air.

 

could be hard to notice, but like it was said spray some carb cleaner around the intake area and if the RPMS change you got a leak somewhere you just sprayed.

 

Not in Tacoma but 2001 Sienna (sold few years ago) I had this code. Pulled MAF sensor and saw all kind of crap on it. I used contact cleaner (from home depot) and made MAF sensor guts shiny again. Then I replaced air filter and cleaned entire intake from dust and other crap. ECL never came back again.

PO either didn't put air filter correctly or maybe never changed it. Actually I'm sure that Sienna was serviced by some redneck mechanic who did not know a shit about modern cars. In few places I found imperial nut forced on metric bolt, some vacuum hoses were swapped, some were "repaired" with duct tape. Horrible.