I have check engine sign on my 2000 RX 300 for two weeks. I scaned with Snapon advance scanner and it says code 0171 system too lean Bank # 1.
I read the explanations of this code in the book, it says MAF sensor, Catalyst, Oxygen sensor. One week before I clear the code and the check engine sign gone but came back after a week. Now I change the oxygen sensor on next to engine on top but one day later check engine sign came back. What should I do. Please help me about this.

 

What are the pending codes? P0171 cannot be by itself. By the way, for 2000 RX P0171 means the System is Lean (either Bank 1 or Bank 2).
You changed A/F before catalyst on Bank 2. Might as well check the one on Bank 1.
But first get pending codes, I bet they are gonna be one or more of the following:
P1130, P1133, P1135 (Bank 1 A/F Sensor)
P1150, P1153, P1155 (Bank 2 A/F Sensor)
P0100, P0101 (MAF Sensor)
You also might get P0125

 

Did you clean the MAF sensor?

 

I have only one code 0171 nothing else. I also cleaned the maf sensor and changed the A/F sensor on bank 1 on the bottom of the engine. But I have the CEL again and the obd code 0171 only.

 

Check again, P0171 never comes alone. You have an OBD-II scanner? If not ask for PENDING codes.

 

my 99 came with P0171 alone. check if you have any exhaust leaks, because that was my problem.

 

clean the maf sensor and check for leaks. i had the same problem last year and i replaced the maf sensor, then two months ago i got P0174
System Too Lean (A/F Lean Malfunction, Bank 2) code i erased it an then the P0171 came back. so i also replaced the O2 sensor after the cat and havent gotten any more codes

 

clean your MAF sensor with throttle body cleaner, clean the seals, reinstall, check your accordion bend for cracks(part of the exhaust that bends by the driveshaft[if you have awd]), disconnect the negative terminal for about a minute and drive 100 miles, the time it takes for the computer to register anything. See if that helps. If that doesn't then you could have a faulty O2 sensor.

 

I cleaned MAF sensor but didnot work. I bought a new MAF sensor from the dealer and installed then the CEL gone.

 

If it comes back..

Like one of the members said earlier..

Jack ur car up...

Start IT

And check if you have any exhaust leaks...U might need a new gasket..

It's not a major repair if u do need one..

Gasket costs like 10 bux..and install is a DIY..but a shop wud do it too

 

i buy my maf from autozone because its only $80 and comes with a 1 year warranty.
i even told them i tried cleaning my sensor and broke it. they still let me exchange it for a new one for free.

 

hi -

this might help you. i have an rx330 and i got the same error code. read my posts.

https://www.clublexus.com/forums/sho...d.php?t=295934