Hi everyone,

I just bought a non running mazda 3 1.6 mzr, after diagnostics i figured it wasn't getting any signal from the camshaft position sensor or the crank position sensor, being both sensors at one i figured that is was probably an electrical fault so i checked the entire engine harness, no problem there. i noticed i wasn't getting any 5V on the vcc side of the sensor, the 5v pullup on the signal side is ok, and the GND is also ok, at that point i used an external power supply to power the sensors with 5V to see if i could get any readings from them, and sure enough the car started right up and died (P0403 exhaust recirculation control fault, i think it's stuck open since the car hasn't ran for over a year and is probably causing the car to die after startup, i'll check that later).

So i confirmed that the 5V wasn't at the sensors and that it was the cause of the non start situation, i then checked straight at the ecu (engine harness disconnected, ignition on) and no 5V either, still 5V on the signal lines. Which leads me to the conclusion that the 5V line might be cut somewhere in the ECU, but i can't seem to find any regulators on the board, does anyone know if the 5V is generated straight from the ECU or is it generated elsewhere? and of course i can't find a pcb schematic anywhere ^^ that would have been really cool but i don't think mazda gives up their secrets like that

has anyone had this problem or a similar one before? i checked all fuses and they are good!

Thanks everyone!