Question about 2003 Toyota Highlander

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What are the causes of check engine light? Can check engine light affect the auto transmission system?

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  • akani Jul 17, 2008

    When the VSC/check engine light was on, the auto transmission could not change to high speed gear. I am wondering what could be the cause of these.

  • akani Jul 18, 2008

    After checking with the computer code reading, found out that: P1730 NC revolution sensor circuit related problem that was causing the check engine light to be steady while driving.
    QUESTION: where can i locate this sensor circuit so that i can change it? Do not have the highlander manual handy



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Have you had your air filter changed or checked recently? If you've had it done somewhere other than the dealership that could be your issue. There is a sensor that connects to the enclosure around the air filter. If it is not correctly reattached after service it will cause the check engine light to come on.
Even if you do discover the issue and correct it, the check engine light will persist for server times you turn the engine on and off but usually by the 3-4th day it will turn off on its own. If you think it's mote serious, take it back in for service.
I can't tell you how many times I've taken my Highlander in for service at a non- Toyota dealer (bc I travel for work) and the check engine light comes on bc they check the air filter and neglect to reattach the sensor. Hope this helps.

Posted on Feb 04, 2012

  • No1attheHelm Feb 04, 2012

    I grew up around card (yes-I'm female) and I also know a dealer will reach at straws to tell you something very expensive is wrong with your car when there are simple fixes you can make yourself. The wire from my heat control knob came loose about 3 years ago. The dealer wanted $1200 to replace the board. I took the dash apart and soldered the wire back myself. I have no experience using a soldering gun but I read up on it, learned how to do it and saved myself $1180.
    Whomever is hosting this form, thank you. It's very beneficial. Especially in these economic times.


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If your Highlander is a 2005 model your may be able to have it checked out under warranty; I own one too (but 2003-- 4 cylinder) under paid WARRANTY.
I had a "check engine light" problem with my 2005 Toyota Corolla, plus transmission "jumping" into Reverse, 10 miles per hour driving, and the rest of the shifting gears.
It was corrected under warranty TODAY (3 years of ownership).
You mentioned transmission and I had BOTH subjects that you mentioned with my 2005 Corolla.
Possible sensor/computer part vehicle type problem.
Under my warranty it was FREE for me.
Call your nearest Toyota Dealer and ask for Service Department...look them up on
A diagnostic test runs maybe about $95.00 [for my Toyota Corolla] if not under warranty.
Be warned though, if the warranty period expired you may be paying at least in the $ 800.00's or MORE for a replacement " Computer, Engine Con"...low conservative price, which should include parts & Toyota 2005 Corrola part & labor was listed at $ EXPECT the HIGHLANDER to be priced higher.
Thank goodness my Toyota 2005 Corolla [same type problem] was covered under warranty!!!
Best wishes & luck in you situation.

Posted on Aug 03, 2008

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These days check engine light could be caused by many, many, many things, starting with loose gas cap all the way to pressure line solenoid in your transmission. Your trans operation could be effected by throttle position sensor failure , which would turn the check engine light on if it failed and so on. Like I said MANY, MANY things could turn it on.

Posted on Jul 17, 2008

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Take the vehicle to an auto electric shop to try to get at the wiring problem in the car's wiring harness to try to correct, or else, the engine light will stay lit while driving.

Good luck on this repair.

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