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Ask Ron Z. Your Own Question
Ron Z.
Ron Z., - Lexus Tech -
Category: Lexus
Satisfied Customers: 18791
Experience:  18+yrs experience. State Inspector and Lexus Diagnostics
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My VSC and check engine light are on, That's it, the VSC and

Customer Question

My VSC and check engine light are on
JA: Sometimes things that you think will be really complicated end up being easy to fix with a Lexus. The Lexus Mechanic I'm going to connect you with knows all the tricks and shortcuts. Tell me a bit more about what's going on so he can help you best.
Customer: That's it, the VSC and check engine light just came on. I know there is a hose that may not have been attached correctly, but I forget where it is.
JA: Are you hoping to fix this yourself?
Customer: Yes, I did it years ago after speaking to someone at Lexus and they told be where to check if I had an oil change recently
JA: Great! What have you tried so far?
Customer: I've opened the hood so far
JA: Is there anything else the Lexus Mechanic should be aware of about your Lexus?
Customer: no that's the only issue I'm having
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Lexus Mechanic about your situation and then connect you two.
Submitted: 1 year ago.
Category: Lexus
Expert:  Ron Z. replied 1 year ago.

When the Check Engine light comes on, the VSC light is also set, which turns this system off. This is a self-preservation mechanism, in case the reason the Check Engine Light is on can harm or effect the VSC system. So- fix the reason why the Engine Light is on, and the VSC system will come back online.

When the Check Engine light comes on, this is the on-board computer's way of telling you it sees a problem in one of the monitored systems. Unfortunately, there are literally 100's of parts and sensors monitored in various systems, and to take a "guess" as to which part/sensor in which system is faulty, is virtually impossible. However, if you are not experiencing any drivability issues such as skipping, stalling, shifting problems, etc, then more than likely, the problem is going to lie in the EVAP (emissions control/recovery) system. Very commonly, this could be a faulty, loose or missing fuel cap or even putting fuel in while the vehicle is running can set the light. Check the underside of the fuel cap for any cracks or signs of defects that may keep the cap from sealing correctly. If there are any doubts about the inspection of the cap, replace it. Keep in mind, you will need a cap that meets OE Specs. Those "universal" or "locking" fuel caps sold at after market parts stores do not meet OE specs, and will not seal the system correctly. Check the top of the fuel filler neck for any signs of damage or debris. Check under the vehicle, around the rear areas of the vehicle, looking for any vacuum lines that have dry-rot cracks, holes or loose/missing connections. If these all check out, then the best thing to do at this point is to have the Diagnostic Trouble Codes (aka "p-codes") read from the on-board computer. These p-codes are what is used as a "starting point" for the diagnosis and will tell which part/sensor, in which system, has the fault. There isn't a Mechanic on the planet that can tell you what is wrong with the vehicle just by "looking" at the Engine Light. Every single Mechanic's first course of action WILL be to obtain the p-codes. It's standard diagnostic procedure. Once you get these p-codes you can more accurately and efficiently diagnose the problem and then make the correct repair. You can have these p-codes read FREE (except in California) at any local "big chain" part store (ie. AutoZone, PepBoys, Advanced, etc). If my answer has helped you, please help me by leaving a rating or accepting my answer so I may be credited. Rating or accepting my answer does not cost you extra. It allows me to be credited for my work. Please rate or accept. You can ask follow-up questions after you rate or accept.

Customer: replied 1 year ago.
I want to know where to find the hose that needs to be attached because it wasn't attached correctly after oil change
Customer: replied 1 year ago.
You did not answer my question
Expert:  Ron Z. replied 1 year ago.

There are literally hundreds of vacuum lines on this vehicle. Can you be a bit more specific?

Customer: replied 1 year ago.
Yeah there is a hose that gets disconnected when the air filter is removed during an oil change. It's somewhere behind the air filter
Expert:  Ron Z. replied 1 year ago.

May I have the year and model of this Lexus?

Customer: replied 1 year ago.
2002 RX 300
Expert:  Ron Z. replied 1 year ago.

Ok. Not quite sure why they would unplug a hose to do an oil change. There is absolutely no reason for this. The only thing I can think of near the Air Filter Housing would be VSV for the Canister. For an image location, click here: https://www.dropbox.com/s/fsqkvl9bafl0hih/rx-1.jpg?dl=0