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Ask Ron Z. Your Own Question
Ron Z.
Ron Z., - Lexus Tech -
Category: Lexus
Satisfied Customers: 17804
Experience:  18+yrs experience. State Inspector and Lexus Diagnostics
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There are 3 lights that came on. The 4 low( for thesystem),

Customer Question

There are 3 lights that came on. The 4 low( for the*****system), the Trac off light, and the check engine light. My wife drove the car about 2-3 miles and everything seemed fine. Is there anyway that I can reset the warning lights to off. That way I can see if they come on separately and in what order.What she did in advance of these lights coming on was to try and start the car twice without the keys being in the car(she thought they were in her purse)
JA: Does the light stay on, or does it blink?
Customer: which light?
JA: What is the model/year of your Lexus?
Customer: 2013 GX 460
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: Just want to re-set the lights,then I will take it to dealer(which is 2 hours away)
JA: Anything else you think the mechanic should know?
Customer: No, this is the 5th Lexus I've had and never seen these lights before,but I also don't think I've ever tried to start it twice without keys in the car.
Submitted: 2 months ago.
Category: Lexus
Expert:  Ron Z. replied 2 months ago.

When the Check Engine light comes on, the Trac and 4WD lights are also set, which turns these systems off. This is a self-preservation mechanism, in case the reason the Check Engine Light is on can harm or effect the VSC/4WD systems. So- fix the reason why the Engine Light is on, and the VSC and 4WD systems 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 you'd like to try and reset the system, you can do so by removing the "NEG" cable from the battery for a minimum of 5 minutes. Or, you can have the local parts store use the scan-tool to clear them (except in California). Keep in mind- if the reason the check engine light is on was not addressed or repaired incorrectly, the lights will return within 50-75 miles (sooner depending on where the problem lies).

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Expert:  Ron Z. replied 2 months ago.

If there are any other questions you have on this, or there was something you were hoping to have addressed that I may have missed in my answer... please feel free to reply and ask!

Expert:  Ron Z. replied 2 months ago.

Hi! I noticed this thread was still open and you did not leave a rating , so I wanted to check in and see if there was anything else I could do for you on this issue? Did you have any other questions? Was there something I missed that you wanted addressed? If you have no further questions and simply forgot to leave a rating, please take a second and use the stars at the top of the page to rate our Q&A session. Thank-you!

Expert:  Ron Z. replied 2 months ago.


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