I have s300 and now i noticed my ecu has a solid red light when turning ignition on instead of green. I do not have spark and fuel pump does not come on. also, CEL is very dim but illuminated when ignition is turned on.

 

back from the dead. my beater is now doing this EXACT same thing! Check engine lamp dim, no fuel pump prime, crank, no start! please help! is my ecu fried?

 

Version? How old? The battery backup up RAM has a life of 10 years, hence the question. The S300 V2 & V3 don't use battery backup up RAM, so don't have the problem. With heat the battery doesn't last as long. If the vehicle is left without battery power that decreases the battery life as well.

 

Mine did the same thing when i had a wire leading to the fuse box ground out, no spark no fuel and the red light. I had to re-flash my ecu, and it ran perfect after that. check all your wires you might have a bad connection grounded it out. On stock ecu's you can take the cover off and smell the circuit board, if it smells like fish the ecu is fried. capacitors are full of fish oil, and the will leak when they are bad.