TRD Cold Air Intake/Mass Air Flow Sensor/Check Engine Light Question

[FrijolPower]

First of all, some background on my truck, I have a 2008 Double Cab with the TRD Off Road Package and the 4.0 V6. I have done a couple upgrades, the relevant ones are a TRD Catback (about 2 and a half years ago) and a TRD Cold Air Intake (about 2 years ago).

About 4 months ago my "Check Engine" light turned on, I immediately took it to the dealer so they could run a diagnostic and tell me what was wrong with it. The code came back a problem with the Mass Air Flow Sensor. A new Mass Air Flow Sensor and $300 later I was on my way.

About 2 months later my "Check Engine" light turned on again. Again that same day drove down to the dealer to have it checked out (and enjoy the warranty on their service), the diagnostic code was Mass Air Flow Sensor. Since they couldn't find anything else wrong with it they assumed it was defective, and swapped it out - for free this time.

About a month and a half later, again, my "Check Engine" light turned on, so again, I reluctantly drive down to the same dealer, hopefully it was covered by their service warranty again. Again the diagnostic code came back as Mass Air Flow Sensor, but this time they say when I cleaned my TRD Cold Air Intake filter I must have used too much oil and it had blown on the sensor causing a short. In other words, they swapped out the Mass Air Flow Sensor for a quick $250 and instructed me to go home and reclean out the filter and use less oil this time. So I did.

About 2 weeks later (can you guess what happens next?) my "Check Engine" light turns on... again, and again I drive down to the same dealer - I must be a glutton for misery. The diagnostic - Mass Air Flow Sensor. This time they keep my truck for 2 and a half days, ran every test and monitor they had available. They couldn't find anything wrong with the Mass Air Flow Sensor. They suspected something is wrong with my TRD Cold Air Intake, so for a test, they swapped it out with a stock and found that it "solved" the problem. So what they found was I was triggering a CODE P0101 - "MASS AIRFLOW CIRCUIT RANGE/PERFORMANCE PROBLEM." What they tell me, my TRD Cold Air Intake is messing with the air/fuel ratio. The normal Long Fuel Trim Percentages are 5.5 to 8.5, with my TRD Cold Air Intake I run at 19.5 to 22.5, which is still under the max allowed of 30, but there are instances when it spikes above 30, triggering the Code P101 and my "Check Engine" light.

Their recommendation? Swap out my TRD Cold Air Intake for a stock, or buy a new TRD Cold Air Intake, or run it as is since they cleaned everything out really good and it might have "fixed" it.

I am still not comfortable with what they are telling me. I have had my TRD Cold Air Intake for about 2 years and have never had a problem, so my question is has anybody else ran into similar issues, if so what did you do? Or if you haven't but have some insight on what is really going let me know.

Thank you!

M

[momsintruder]

yeah I'm having the same problem with my 3.4 I have caused from know and it keeps a code po 0171 lean code and I put my stock back on and it clears up but the gas mileage is so much better with the a cai I want to keep it but no answers for me either. if u find out let me know.

[BamaToy1997]

First thing I will say, is that a long term fuel trim of +5.5 to +8.5 is STILL too high. You are showing to be running lean, even WITH their test. A MAF code can also be set because of unmetered air. Basically a vacuum leak. With a small LTFT of 5-8 it will be a small leak. That is what I am suggesting to look for first. After you get THAT part solved, I would look to see if the code returns, and go from there. Many CAI systems flow much better than factory air intakes, and this can cause the computer a bit of confusion because at "X" RPM, and "Y" engine load and "Z" air temperature, the computer expects to see a specific, preprogrammed airflow. IF the restriction in the air intake is lower than expected, it can set a MAF code.

All of that aside, even a free-flowing intake system should not be running LTFT numbers in the 20s or 30s. I have run PLENTY of vehicles in my shop during diagnosis with unrestricted airflow, and none of them have EVER seen LTFT numbers like that. I think they are just looking at the code itself, and not looking at all the different problems that can set that code. A performance code is not a solid indicator that the sensor itself is bad. Personally I would never use a wet-CAI system. They are right that a wet-CAI system CAN cause premature failure of a MAF, as well as erroneous data, which CAN (Not always will) throw off FT numbers.

[650H1]

if you have the 2nd gen TRD intake, you need to trim part of the plastic tubing so it doesnt fuck with your air intake in turn creating this problem for you.

http://www.youtube.com/watch?v=TfMpeTdseMU

[FrijolPower]

Thanks for the help!

[toytaco1]

I had to drill holes on mine but def a fail on TRD's part