NYCGeordie

RX300 2001, 175k miles. Check engine light and VSC displaying. Have had a number of mechanics try to diagnose problem where after initial start up and reaching overdrive vehicle will not upshift to overdrive after slowing and entering lower gear. Found that stopping, turning off engine, then restarting will enable overdrive but slowing to a lower gear still prevents upshift to overdrive. One diagnosis indicated a possible gearbox issue, another knock sensors, and another running lean. After mechanic checked the air filter and seeing it was clogged that seemed to fix the warning lights. He suggested I drive and bring it back the next day to see if that fixed the issue. At first I though the overdrive issue had been fixed but by the time I got home the warning lights were on again and unable to shift to overdrive. Love this car and would hate to lose it if it is a costly gearbox issue. Any advice or similar experiences would be most welcome.

salimshah

Please post the error codes.

Your mechanic should have the information. You can visit auto parts shop and they can connect and OBDII reader and tell you the codes. The readers have come down in price and you may like to own one too.

Another thing I would suggest is read the "having problems start here sticky thread". It will answer or guide you enough to ask questions that can answered the first time you post them.

Salim

Bill Dowd

Have you changed your transmission fluid recently or has it been a long time, dirty trans fluid can cause problems in the valve body. Causing the overdrive not to engage this only a shot in the dark but it happened to me in a Buick and
the fluid was new and it was synthetic trans fluid and the valve body caused my over drive not to work. if you are a DIY person I would recommend checking the fluid and if it dark brown drop the pan replace the filter and use Max Life synthetic fluid.
after that do 2-3 drops and fills thru the drain plug also buy some crush washers for the plug. when you start the car up go thru all the gears to let the fluid flow thru the trans.

NYCGeordie

NYCGeordie

salimshah

You cant beet free ... as stated in my earlier reply.

Check amazon for OBD11 ... the cheap ones are dumb and they become expensive with features.

Salim

Lexmus

For reading codes any OBDII reader will do. I recommend a bluetooth reader like this one, and use the torque app on your android phone/device. It gives access to a lot of sensor data as well as the codes.

I think everyone should have an OBD2 reader in their car, but especially when driving an older one like the RX300.

NYCGeordie

To all who responded, thanks. I found a mechanic who was able to identify the codes. Turns out it was the sensors and he replaced the OEM's with harness I'd purchased via Amazon. Turns out there was also a need to top up transmission fluid due to a hose leak which will be fixed next week. So far, the sensor install, oil change and transmission fluid top up came to $538 and she's shifting like a charm so I'm one happy camper. Thanks again.

ukrkoz

BTW, over the counter OBD2 scanners will not read transmission codes. From what I recall, you need a CAN BUS capable scanner. Even with that, transmission codes are propriatary for the most of them and can be read only with licensed software. You also need advanced scanner to read ABS/VSC/brake codes. Things they use at parts stores are just generic basic readers.
Anyway. Good you have cause pinpointed. That's hald the fix.