Not shifting into overdrive and check engine light

The Check Engine Light is on? Did you read the DTCs.

The second link has the answer, the first link says it is a known issue. It is times like this you need the Dealership or a good auto electrician.

Transmission won't shift to third until temp rise

ClubLexus https://www.clublexus.com > forums > 713188-transm...
Apr 1, 2017 - Transmission won't shift to third until temp rise ... The solution is to drive slow and keep rpms at 2.5k and 3k at max till the engine and transmission warm up.
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Won't shift from 3rd to 4th gear - Lexus Forum Discussion
Jan 25, 2011
RX300 not shifting into overdrive. - Lexus Forum Discussion
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FIRST POST! RX300 no 4th gear a full year. Fixes? - ClubLexus
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More results from www.clublexus.com

Owner of Lexus RX300 with 182000 miles. Recently the ...

JustAnswer https://www.justanswer.com > lexus > 3wsxt-lexus-rx3...
Aug 22, 2010 - Recently the transmission won't go into overdrive. Stays in 3rd gear like when you press the o/d button to do so. When car is cold (live in ...
1 answer · Top answer: Hello and thank you for using just answer! The check engine light is on correct?

https://www.google.com/search?q=Lexus+RX300+will+shift+into+overdrive+once%2C+and+after+slowing+down+it+won%27t+go+past+3rd+gear

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mate sounds like u needa find ya self a good mechanic and stick to them only, have u checked your oil mite need a top up or a change

Start by checking the least expensive items:

Make sure you are not activating the O/D switch in the shift stick inadvertently.

Look at the display panel, if the "Eng" light is on, you must get the code and repair the affected item. If you have knock sensors and/or oxygen sensors malfunctions that may prevent the transmission from shifting to O/D.

Check the ground cables located in the engine compartment, especially the ones behind the air intake manifold. If they are loose or broken it affects the ECU (car computer) and causes the transmission to work erratically. If they become disconnected it may burn the ECU and shut down the car.

Now going to more profound mechanics, it could be a sticking shift solenoid valve, your RX300 transmission have five of those located were the transmission oil strainer (filter) is. It can also be an ECU malfunction and/or related to the wiring from the ECU to the transmission connectors.

Always start from the least expensive and recheck the obvious. Good luck.

My Lexus es 300 most often when engine is warm will not shift in to last gear. Stop engine start it will shift ok when engine is cool. engine pings kock senores. When in gear at high speed the car runs like new?? Car run bad in hot weather. VSC light on. Red light looks a circle with red line through it comes on not always..

The 1999-2003 Lexus RX300 models have a common failure of the engine computer that causes the harsh shifting of the transmission. You need to get the computer (ECM - Engine Control Module) rebuilt or replaced before it causes permanent damage to the transmission. Even if the transmission is already ruined, the ECM will still need to be repaired. Most often, the transmission is fine though, and rebuilding the ECM will restore the smooth shifts that the Lexus should have. Circuit Board Medics can rebuild the ECM and reprogram it so that you only have to plug it back in when you get it back. See the link below:

http://circuitboardmedics.com/1999-2003-lexus-rx300-hard-transmission-shifting-ecm-ecu-computer-repair/

2-4-6 could be a fuel or ignition issue, hopefully not a valve. If you have the engine tested at the dealership they will attach a code reader under dash to analize and this should help pinpoint the problem.

Check for vacuum leaks. ie, vacuum lines them selves, the rubber tube that runs from the air filter to the throttle body. If it has a plastic intake manifold, possibly the rubber port seal gaskets between it and the engine. Lean codes are set when the PCM isn't monitoring all the air coming into the engine (vac leak) or low fuel pressure.

U need a shopmanual..library sec629. Autotrans r so complex it may just b a bad connect etc. Get car scanned to show a datastream. It takes a factory tool..seek a privateshop

yes its related to knock sensor because car is running rich in fuel, and car runs of on safe mode, so overdrive will be off. have you and a friend replace it. remove intake assembly, then intake manifold, but first remove your anifreeze from radiator, trust me you want to remove antifreeze! their are brackets by the fire wall to hold down the manifold, thats the hard part is taking it off and putting that on since not to much space to work on it. on the block you'll see the two knock sensors, has 2 wires each, knock sensors cost between 150- 200 a piece, still cheaper than dealership putting it on. also buy some liquid gasket because you will need that. after putting it all back together reset the ecu and you should be fine,

knock sensor needs replace