my wife was driving the RX300 on the freeway yesterday and the car just quit running and I had to have it towed home. How can you tell if the computer is bad? All the relays and fuses check ok. I pulled the 7.5 amp fuse for EC1 and still no fire. Any suggestions on where to proceed from here?

 

Did you check the gas gauge?

 

there is sufficient gas in the car. over half tank

 

Ok. A sudden and massive failure of the ECU is extremely unlikely. I would check the fuel system first. See if your fuel pump is running and if it is delivering fuel to the engine.

 

ok. I will check .

 

Is it cranking?

 

Is a timing belt broke ?

 

+1 ^^, sounds like a god possibility.

 

Try the mega thread 'having problems start here',

When you say died or not running .. it needs some additional information.

Salim

 

That was my next thing to look at. the car turns over but it seems to not have any drag on the starter. Turns to easy. the car has well over the 100,000 miles.

 

Could be timing belt. Hope not.

 

On my other car I can check if the timing belt is rotating by opening the engine oil fillup cap in the valve cover and peeking. I don't know about the Lexus but if you can try that.

 

Won't work in the RX; there is a baffle that prevents you from being able to see the camshafts and other parts of the valve train.

 

Yeah that stupid baffle prevents that from happening. I would also like to see how clean or dirty it is under there with out having to remove the whole valve cover.