I have a 99 SC 300 stock motor.I have a crank but no start issue. Hooked up a scanner to it had no comm to PCM.I noticed that the check engine light does not light up.Both EFI fuses are good IGN fuse is good swapped the EFI relay with the defroster ,same result cranks no start.Does anyone know what wires at the under hood fuse box I should be checking and what wires at the PCM should turns the PCM on??

 

i would hold off on the pcm for right now. u NEED 3 things for that car to start, compression, fuel and spark i would verify that you have all three before continuing and further

 

Yeah but if the pcm is not turning on then you won't have spark or fuel.

 

you have gas?

 

yes car has gas

 

There is a fuse for the Check Engine Light. It's one of those ECU fuses located in the engine compartment. I think it's fuse 7.5 rated. Check all of the fuses to be positive. When CEL is working again, it should start. Unless, the CEL has a burnt bulb. GL

 

Yea checked that fuse it's the efi fuse which has power. What I need is wiring diagram to find out what wires turn on the PCM

 

The OBD 2 (DLC) fuse is on the driver side, for 7.5 AMP Your best bet is to check ALL fuses. Which ever is burnt replace. Start from engine compartment then driver kick panel/fuse box.

 

exactly why you should check to see if you have either.......