3sm1l

Hello,


So about a month ago I decided to clean the Throttle Body on my 06 IS350. I purchased a can of TB Cleaner and cleaned the outside plate of the TB with a rag. After I was finished cleaning, I started the car and it was idling on high RPMS, about 2-2.5k and the check engine light came on, I grabbed my OBDII reader and the error says "System Too Lean" on both banks. I read on some forums about that behavior and for what i understood, it was normal and I just needed to drive it for a while and then the RPMS would settle to normal levels. About 2 weeks after i cleaned the TB, the RPMS went to normal but the check engine light remained. Since then, I've replaced the MAF with another one, and reinstalled the air intake system but after a while, the error comes back.

What is weird though is that I've tried to reset the ECU, both ways, by disconnecting the battery and by removing the EFI and ETCS fuses but the car doesn't enter in learning mode, it stays as if i did nothing.

What could be happening?

MikeFig82

iTrader: (13)

Make sure all your hoses are connected correctly. Check the intake tube to throttle body. Also the crank case hose to the intake is attached. Maybe one is not secured correctly.

Another is failing 02 sensors. Can you read date on your OBDII scanner?

3sm1l

Thanks Tlts82 for your response.

That's what I did, i checked all the hoses and i don't see nothing lose or not connected.

Question, if there is a hose that is not connected correctly, that might cause the ECU to not reset?

MikeFig82

iTrader: (13)

How long are you letting the ecu reset? Leave it like 30 min or so. If you don't have to reprogram your clock, or radio stations. Your not letting it fully reset.

3sm1l

Which way you recommend? Fuse pull or Battery reset? By removing the fuses i don't have to set my clock or radio stations.

MikeFig82

iTrader: (13)

my personal preference is disconnecting the negative battery terminal.

MikeFig82

iTrader: (13)

Did you replace the MAF with a oem one? If the code came back you can probably rule it out as not faulty. Cheapest route is to check for a vacuum leak somewhere. Then go from there.

Mrfix

MAF should be OEM (Denso), this is very important. Check all connections. Hopefully you didn't push on the Butterfly in the TB when you were cleaning it with the car battery still connected. Typically it is ok to move it when the unit has no power but never when it is connected to power.

3sm1l

What would happen if I moved the TB with the battery still connected? I didn't removed the TB from the car.

Mrfix

Since your still getting the same code as before make sure you use the OEM MAF.

MAF's are one of those parts where you always try to use the OEM one. After market MAF's more often than not don't work correctly. Rockauto sells the OEM Denso for about $87.


When the throttle body is electronic/fly by wire you can't just push the butterfly open while it's still connected to the vehicle and start cleaning. It is programed with the ECU and doing that can require reprogramming.

What you're suppose to do is get an assistant to get in the car and turn the key to the on position and press the accelerator down to open the butterfly so you can spray cleaner in there and avoid touching the butterfly.

Now if you want to do it properly without worry, you can unplug the throttle body and remove it from the vehicle (take the battery cables off first). Once it is completely disconnected and removed you can move the butterfly around without worry while you scrub and clean the surfaces.

I have done my Avalon and Venza by removing them for the vehicle.

I did the IS350 with an assistant and didn't touch the butterfly. After the cleaning, Cylinder number 4 had a misfire code. I cleared it with Torque Pro and the vehicle is fine.

Gville350

iTrader: (10)

This is why I warn those attempting the TB cleaning NOT to mess with the throttle plate (butterfly). Hope you can figure it out!

3sm1l

OK. I reinstalled everything and I'm keeping an eye on the short and long term fuel trims by using torque pro (from what I understand by checking these parameters, I can see how the engine is reacting and if it will throw me a lean/code.

It's been two days since I did the reinstall and the short term fuel trims hover around +/- 1.6 a lot of the time it stays at 0. And some times it jumps up to - 10 but only when I'm braking hard after I big acceleration.

The long term fuel trim stays around + /- 5. But also stays around 0 on acceleration. Throttle plate us 16.5% on idle.

How are these values?

MikeFig82

iTrader: (13)

Some good info here.

http://m.autoserviceprofessional.com/article/94982/Fuel-trim-How-it-works-and-how-to-make-it-work-for-you