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Hello,
My 2010 RX 350 has trouble codes P0170 and P0174: the system is too lean in banks 1 and 2. The Long-term trim is +35% and the short-term trim is +15% at ide. The long-term trim is +30% and short-term trim is +5% at 2500 rpm. I also checked the reading of MAF sensor, it is 2 g/s at ide, and 6-7 at 2000 rpm. I am not sure if these values are normal or not. Because I don't know the normal reading of MAF sensor, I couldn't tell if the MAF sensor is bad or not. Does anyone know these specs?
Hello,
My 2010 RX 350 has trouble codes P0170 and P0174: the system is too lean in banks 1 and 2. The Long-term trim is +35% and the short-term trim is +15% at ide. The long-term trim is +30% and short-term trim is +5% at 2500 rpm. I also checked the reading of MAF sensor, it is 2 g/s at ide, and 6-7 at 2000 rpm. I am not sure if these values are normal or not. Because I don't know the normal reading of MAF sensor, I couldn't tell if the MAF sensor is bad or not. Does anyone know these specs?
Thanks!
I am not certain that you can test or confirm a MAF sensor reading while the engine is running. It just reads the airflow. The lean codes generally means that a leak has occurred that is allowing airflow to get past the MAF sensor(intake manifold gasket leak, vacuum hose leak,etc) that is causing a conflicting reading with the Air/fuel ratio sensors in the exhaust.
However, you can test your MAF with the engine not running with a Tech Stream or scan tool that can read/test the MAF sensor for a .53 g/s or less reading.
I am not certain that you can test or confirm a MAF sensor reading while the engine is running. It just reads the airflow. The lean codes generally means that a leak has occurred that is allowing airflow to get past the MAF sensor(intake manifold gasket leak, vacuum hose leak,etc) that is causing a conflicting reading with the Air/fuel ratio sensors in the exhaust.
However, you can test your MAF with the engine not running with a Tech Stream or scan tool that can read/test the MAF sensor for a .53 g/s or less reading.
Thank you a lot for your sharing! I will test it right now! It surprises me that there are warm-hearted people here. Have a nice day!
I saw some videos on YouTube. Some people just spray some water onto the intake manifold and some pipe connections. If there's a leak, the engine will shake a little bit.
I saw some videos on YouTube. Some people just spray some water onto the intake manifold and some pipe connections. If there's a leak, the engine will shake a little bit.
Please do not reach out or perform tests that you come across on the net.
There is so much information on the wild wild net and regrettably there is no way to filter out the chaff from real.
The proper way to test for vacuum leak is "smoke test" with a smoke generating machine. Please look that up. There are other hacks like propane and starting fluid [they need to be done with care].
The only water and intake test is a hack to clean cylinder heads, but then again it can damage lot more as water in the intake adds incompressible fluid in a closed combustion chamber.
Combustion due to emission control is a closed loop system. It can be hard to diagnose as the system keeps adjusting itself and the error messages can be due to the shift by a problem in a far related component of the loop.
Please do not reach out or perform tests that you come across on the net.
There is so much information on the wild wild net and regrettably there is no way to filter out the chaff from real.
The proper way to test for vacuum leak is "smoke test" with a smoke generating machine. Please look that up. There are other hacks like propane and starting fluid [they need to be done with care].
The only water and intake test is a hack to clean cylinder heads, but then again it can damage lot more as water in the intake adds incompressible fluid in a closed combustion chamber.
Combustion due to emission control is a closed loop system. It can be hard to diagnose as the system keeps adjusting itself and the error messages can be due to the shift by a problem in a far related component of the loop.
Salim
Thanks, Salim for your valuable suggestions! You are so thoughtful. I will try to DIY a smoke machine to do the smoke test, probably on weekends.
Thanks, Salim for your valuable suggestions! You are so thoughtful. I will try to DIY a smoke machine to do the smoke test, probably on weekends.
Some one in first gen RX posted that they had PepBoys conduct the smoke test. The identified the leaks but were not able to fix as they could not find proper part.
Some one in first gen RX posted that they had PepBoys conduct the smoke test. The identified the leaks but were not able to fix as they could not find proper part.
Salim
Thanks for the information! I am a DIY guy and enjoy repairing cars and saving money, although I am not good at it now. I bought this 2010 RX 350 with 140K miles on it from my friend, for $5500. One issue is P0170 and P0174, and another one is suspension noises from the rear passenger side when over bumps.
The noise in the rear may be from worn rear trailing arm bushings as that is a known wear item. The rear trailing arm may need to be replaced. First get it diagnosed properly before throwing parts at it. Make sure the rear shocks are not leaking, that their bushings are intact and that the rear sway bar links are intact.
I used Mevotech rear trailing arms from Rock Auto.
It is a difficult job to do at home with floor jacks and lots of tools and I have all those, and years of doing my own car repair experience including suspension work. The angles to get at the bolts are best done with it on a lift. Any local independent shop can do this job if it is needed.
Your rear suspension noise may be a broken exhaust heat shield in the right rear area. Mine broke loose on one end and I epoxied it back on. no problems since then.
Just a thought.
The noise in the rear may be from worn rear trailing arm bushings as that is a known wear item. The rear trailing arm may need to be replaced. First get it diagnosed properly before throwing parts at it. Make sure the rear shocks are not leaking, that their bushings are intact and that the rear sway bar links are intact.
I used Mevotech rear trailing arms from Rock Auto.
It is a difficult job to do at home with floor jacks and lots of tools and I have all those, and years of doing my own car repair experience including suspension work. The angles to get at the bolts are best done with it on a lift. Any local independent shop can do this job if it is needed.
Your rear suspension noise may be a broken exhaust heat shield in the right rear area. Mine broke loose on one end and I epoxied it back on. no problems since then.
Just a thought.
Thank you both for your thoughts! Actually, I have already checked a little bit but didn't find anywhere loose or broken. It seems that checking for noises needs much experience.
Mass air flow sensor normal reading ?
