What a dissapointment! The check engine which was fixed no more than 10 days ago is already back!
The car has been more at the shop than at home! This will be the 3rd time in less than a month!
Did I buy a lemon?? The one in a million one?? Once again I will call Lexus and have them check the car again. They just replaced the canister and some hoses, I wonder what is wrong now!

 

They probably didn't find the real cause. Even though they hook it up to a computer, it doesn't always reveal the problem. The dealer has to be willing to really look and not quit until they find the problem. Mine was an animal chewing the wires, moving things around and building a nest inside! They did cover it under the warranty. You do need a good dealer. From your earliar posts I'd say you'd better find a better dealer and let Lexus know!

 

1. trouble codes can be caused by sensors that send the wrong signal or no signal to the ECU.
No signal is usually a sign that the sensor has died. Wrong signal is usually due to a faulty sensor or a sensor that is translating the input from something else incorrectly. Dealerships go with the "replace the sensor that tripped the trouble code" rather than find out why the wrong signal was sent. It is more cost effective and profitable for them. However, the shop manuals are designed with a diagnostic direction. Test this voltage, try this connection, etc. it should be between this ohms and that ohms, etc. This takes time, and sometimes it is just quicker to replace.

2. It can also be that the part replaced is faulty. Remote possibility but it happens.

3. The correction of one part or sensor may now uncover another problem. Find out what the new code is.

good luck.

steviej

 

So a buddy of mine who works as master Toyota mechanic checked my car with the code reader and we found P4400. We started to inspect everything and he found a really bent hose that leads to the air intake, we fixed it and erased the code and so far so good. He said the car needs to cycle for a week or so and if no check engine by then we fixed the problem. COOL !

 

Yeah P0440 is the basic EVAP malfunction code, at least you didnt have P0446 or P0441 which are EVAP leak codes... Looks like that bent hose could be your problem. But it will take a while for the car to run the EVAP monitor again to check if the problem is fixed. Good luck with that bro! Hope you get it all sorted out!

 

I had them evap codes too but Lexus fixed them for me under warranty by replacing the canister.