I have 2004 Lexus 330 and at 50,000 miles the service light came on. What the probable fix? Thanks.

Pay attention to the dash display and see if any warning light blink.

This should be reset when the oil is changed [ you may be due for service ]. to reset make sure the odometer is set on total miles, make sure the key is off, push on the reset button, turn on igntion key keeping your finger on the button- the mileage numbers will be replaced by a groupe of dashes, they will go out from left to right. Once all are out you should hear a chime- it's reset.

Sometimes the light will stay on for 100-500 miles depending on the fault code. You can disconnect the battery to reset it, but you will have to reset the radio and other memory such as seats mirrors.

Who ask you this much for 72k ????????????
In your owner manual should be service schedule or separate booklet with it.
And 72k miles or km ??????? And were are you at?
Most expensive service is 90k miles - around $1800 but you are not there yet , neither with miles or km.

the coolant needs to be serviced @ 60k according to lexus reccomendation. theres a timing belt that needs to be changed @ 90k miles. I usually just change the coolant with the timing belt because you have to take the water pump off anyway and replace the engine coolant.

i would get it serviced if youre happy with the car theyre known for doing super high milegages,with no problems if you service them,to change over cars will be a false economy

a major service is due at 60000 miles. the light is just a reminder that maintenance is due. is it the message on the nav screen or the one on the dash cluster? if you want to turn it of, hold the trip/od button in while turning the ignition on, keep your foot off the brake, dont start the car. you will see dashes flashing where the od shows miles, hold until its done flashing. and the lite on the dash cluster will go out. it will come back on after 5000 miles. you can go online to lexus.com to review what the services are and what they involve.

how many miles??? is it due for a service at the mileage interval.. was the oil light reset at the last oil change??

Basically, stop driving it until you can get the transmission serviced.
If you can safely jack up the vehicle and support it so it cannot fall on you, you can possible save some money by checking all the electrical connections to the transmission. Sometimes the problem is a loose or bad connection. If that does not work, your safest bet is to bring it to a certified mechanic, especially one who specializes in Lexus.

You need to get another opnion from Lexus. The transmission shouldn't shift like that and it isn't a software issue. This could be a warrenty issue or a recall issue. I would take it to a diffrent dealer.