adi

Hi, yesterday I noticed the engine light and track light came on(my car is a rx300, model 1999) . After I turn off and on the engine only the engine light was on. I went to a local shop and they found code P0171 using an ODB. After reading on the forum someone suggested to disconnect the battery for a few minutes. I did that and the light was not on anymore. This morning I took the car to the State Inspection Center and it passed.
Here are my questions:
#1. Is it possible that the engine light came on as a warning that I need to do the 120k general maintainance check up(my ODO reads 121,200)? and now since I disconnected the battery and the engine light dissapeared everything should be fine.
#2. Or, the engine light will come back and there is a hidden problem.

If is the case#2(there is a hidden problem) then how come I did passed the inspection today?
Thank you for sharing your thoughts.

mikey00

The P0171 indicates that the ECU detected a fuel systen too lean condition. This can usually be fixed by cleaning the MAF sensor. But first wait and see if the error returns. The error has nothing to do with the 120k service. Also in NJ they will fail your car if the engine light is on but you reset it, so it was off. You may be lucky and the error will never return. If it does check here:
https://www.clublexus.com/forums/rx-...de-0171-a.html

adi

thank you, mikey

JBDUFFY1

I have 1999 RX300....It had 100K timing belt done and $3000 more with real engin seal....Son drove it for a couple months with Engine light on. Then Car started bucking...I replaced O2 sensors (2) @ $160.00 ea, That didnt help.
I borrowed code reader and got P1300-P1305-P1310...P1350...all missfire errors. Called Lexus...they are going to Diagnose..but Offfice service guy think Cat Conv shot....

Lexmex

That's because the there is something called readiness monitors for the cats and oxygen sensors that were reset properly, because you drove enough time before your emissions test to reset them.

The P0171 may have come up due to weather related reasons and the fact that are vehicles are older and/or the sensors are getting older.

Luismond

Please excuse me to maybe ask this stupid question.
I just sign in in this forum and I've been trying more than long enough to find the way to post a new thread and I can't.
Can anybody give me a hand with this?
Thanks a lot.

salimshah

retracted retracted

Luismond

Thank you very much
Luis

Luismond

Hi guys
I have a 99 RX300. State inspection already expired.
Got the CEL (check engine light) on, went to Autozone to get the code and was the P0171.

Definition:System to lean - bank 1 (Cyl. #1 denotes bank 1)
Probable cause:
Lean air/fuel ratio-fuel injector or vacuum leak
MAF sensor concern
ECT sensor fault
Faulty HO2 (heated oxygen sensor)

I checked for vacuum leaks, didn't find any.
Cleaned MAF sensor
And disconnected battery to reset CEL.

Two days later I went to get the stated inspection done and passed.
Only one system was not ready which is OK to pass the inspection in Texas.
"Evap" was not ready.

Question 1 is:

What does Evap refer to?

Then, a week later CEL came back on in the morning, I drove it like regularly and the same day in the evening CEL went off.
The engine always performed OK, no malfunction at all.

Question 2 is:

Can anybody tell me what it could be going on?

Question 3 is:

Should I expect CEL to come back on or that's it, problem solved?

Thank you all very much in advance.

Luis

Aprazur

Change the PCV valve (Positive Crankcase Ventilation) and the rubber grommet it fits in. Its leaking vacuum. Cheap fix ($5 to $10) including the grommet.

The PCV valve is at the right/rear (passenger side). It sits under the edge of the fire wall on top of the front corner of the rear valve cover. It has a black vacuum hose connected to it.

JS