RX - 1st Gen (1999-2003) Discussion topics related to the 1999 -2003 RX300 models

Check engine light: vacuum leak

Old 01-02-07, 04:48 PM
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genijet
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Default Check engine light: vacuum leak

I brought my 1999 RX300 to the dealer because the engine check light went on and was told that it was a vacuum leak. How can I find out where the leak is?
Old 01-02-07, 09:19 PM
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Lexmex
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Originally Posted by genijet
I brought my 1999 RX300 to the dealer because the engine check light went on and was told that it was a vacuum leak. How can I find out where the leak is?
Do you know what the code number was for the light, as vacuum leak can pop up in a number of places? One common issues is the hose that goes on to the back of the air box being lose or not attached.
Old 01-03-07, 03:20 PM
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genijet
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Default Lexus Vacuum System Diagram

Please show me where the"air box" is in the attached diagram and how I might locate the leak. Thanks, Carl
Attached Thumbnails Check engine light: vacuum leak-lexus-vacuum-system-3.jpg  
Old 01-03-07, 05:18 PM
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mikey00
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Originally Posted by genijet
Please show me where the"air box" is in the attached diagram and how I might locate the leak. Thanks, Carl
The hose lexmex is referring to is part of the evap system and when disconnected will through off P0440, P441 and P0446 codes. This is a common problem as it is very easy to disconnect the hose when lifting up the top of the air box to check the air filter. The hose is located behind the air box and connected to the top/back of the lid. It is directly under the brake fluid resovoir. The hose connects to a metal tube about 10" down. This is where it usually disconnects.
Old 01-04-07, 12:50 PM
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genijet
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The hose connection to the metal tube was secure. I could not find the canister to check its 2 connections. Advise me here.
Is it possible the light goes on automatically after so many miles?
Old 01-04-07, 01:36 PM
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Lexmex
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Originally Posted by genijet
The hose connection to the metal tube was secure. I could not find the canister to check its 2 connections. Advise me here.
Is it possible the light goes on automatically after so many miles?
Well, the light can go on for certain reasons. The most common code is the P0171 lean error, which can trigger the light. I have mentioned in the past to stop an autozone and get the code (it is free). The dealer should have given you the code number.

The other thing we do is with the vehicle turned off, pull the EFI fuse out for a few seconds. If it comes back on later, it wasn't something related to climate or air conditions.

However, if you are able to get the code, I would be more than happy to go over it with you in detail to narrow down the causes.
Old 01-04-07, 04:51 PM
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Originally Posted by genijet
The hose connection to the metal tube was secure. I could not find the canister to check its 2 connections. Advise me here.
Is it possible the light goes on automatically after so many miles?
I don't think there is much of a chance that the hose is off at the canister. The metal tube is where it always disconnects from lifting the top of the airbox.
The light does not come on automatically after so many miles. It definetly takes a problem to turn the light on but it could be as simple as a loose gas cap. First reset the light by pulling the battery cable or fuse. If it doesn't return, you're good. If it does, it would be best to either get the code read or get a cheap reader (about $40) and read it yourself. Once you have the code come back to this forum and do a search on it for a lot of info. You could also google it for more generic info.
Can you provide any more info about what happend at the dealer? Did he just say "it's a vacuum leak" and walk away?
Old 01-05-07, 11:00 AM
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Default genijet

Mikey00 Thank You. I Removed The Battery Cable And It Worked The Light Wet Out. Thanks Again Carl
Old 01-05-07, 11:01 AM
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Default genijet

Mikey00 Thank You. I Removed The Battery Cable And It Worked The Light Went Out. Thanks Again Carl
Old 01-05-07, 11:18 AM
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Celebrate, when it stays off after 100 miles or so of driving.

Right now you have cleared the warning condition. The new values will be accumalated with a bit of driving.


Salim
Old 01-05-07, 11:23 AM
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Lexmex
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Originally Posted by salimshah
Celebrate, when it stays off after 100 miles or so of driving.

Right now you have cleared the warning condition. The new values will be accumalated with a bit of driving.

Salim
That reminds me of something. A few times going up to the Texas border my light came on (this was when my RX was pure stock engine-wise) and then (without stopping) the light would go off. I recall reading somewhere that if is just climatological (as opposed to something really wrong), that after turning the vehicle on 3 times, that light will go out.

However, of course the magic of the EFI fuse/negative battery cable works wonders.
Old 01-05-07, 03:55 PM
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Originally Posted by genijet
Mikey00 Thank You. I Removed The Battery Cable And It Worked The Light Went Out. Thanks Again Carl
As Salim already said don't celebrate just yet. If it is a genunine problem the light will be back.
Interesting side note here: My wife called this morning stating that the check engine light came on on her way to work today. My thought was to go to autozone and see if they would read the code for free or buy a cheap code reader. I did a quick search and came up with some on ebay for $16.99 plus shipping. They were brand new with a money back guarantee. They were OBD II, capable of reading multiple codes, could reset the light and had 2 buttons. Some of the earlier cheap ones were lacking some of these features. Once the wife came home I did a quick check of the car and found the plastic ring that snaps around the gas cap to keep it attached to the car when it is removed for fueling had come off. The last time she got gas the attendent (no self serve in NJ) put the ring over the gas tank opening and screwed the cap down using the ring as a gasket of sorts. This must have caused a poor seal and set off the light. I didn't reset the light yet. I am just going to wait to see how long it takes to go out. There is some spec as to the number of cycles it waits.
Old 01-05-07, 06:56 PM
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2000 RX300

The check engine light and VSC control light have been coming on and off lately. Advanced Auto checked the codes tonight (P1130 and P1150)
Both are Air Fuel Ratio Sensor Circuit Range/Performance malfunctions Bank 1 Sensor 1 and Bank 2 Sensor 1.

Seeing it is a performance malfunction and not a response malfunction what does this mean? Also which Air Fuel sensor/s does this refer too? Any help would be appreciated.

Woods
Old 01-06-07, 07:20 AM
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Lexmex
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Originally Posted by woods
2000 RX300

The check engine light and VSC control light have been coming on and off lately. Advanced Auto checked the codes tonight (P1130 and P1150)
Both are Air Fuel Ratio Sensor Circuit Range/Performance malfunctions Bank 1 Sensor 1 and Bank 2 Sensor 1.

Seeing it is a performance malfunction and not a response malfunction what does this mean? Also which Air Fuel sensor/s does this refer too? Any help would be appreciated.

Woods
Woods,

Will go over this in your other post in just a bit.

Saludos,

Lexmex
Old 01-06-07, 11:51 AM
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genijet
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MickeyOO I THOUGHT I FIXTED IT,BUT THE LIGHT CAME ON AGAIN AFTER ABOUT 10 MILES. CARL genijet

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