Thread: B13 ECU, read check engine light!?

So I when i bought my car the check engine light bulb was out (noticed after i bought it) so now i want to know why this check engine light bulb was taken out... I need to check the ecu... Only thing I see to turn is this 3 holed weird looking thing that I can't seem to find a way to turn... Is there some special tool or what?

1.) take out cluster
2.) remove bulb socket (brownish socket, twists out)
3.) Replace bulb
4.) Reverse above steps

Odds are someone was missing a sensor or something (like myself, I have no crankshaft position sensor) and removed the bulb to reduce annoyance from it. Just replace the bulb and do the standard procedure to get the codes.

there's a light on the ECU and if i'm not mistaken that's where you check the codes at? That's the way it is on my brothers 93 240sx but his just needs to be turned with a flat head... i'm talking about on the ECU, I'm fully capable of replacing a simple bulb XD

turn the screw to self diagnostic mode and count the blinks. Theres your code.

where's the screw? is it at the back with the wires? there's something that looks like it's supposed to turn and it has 3 holes that somewhat look like a Y... I know you need to turn the screw and everything else, I'm just asking where is it located?

The screw itself is located on the rear of the ECU where the harness connector sits. It probably still has the protective tape over it, since most don't bother to pull codes using it. IIRC, you turn it fully clockwise with the key in the ACC position, count to three, and then turn it fully counterclockwise. The CEL on the dash will start to blink the codes. Long blink is the first digit, and short blinks are the second digit. 5 long and 5 short means no codes, normal operation.

Only problem is that he doesn't have a CEL bulb installed

To OP: Do not force the screw past the stops while turning, otherwise it's time for a new ECU

the light flashes on the ecu as well if you dont have the cel bulb installed.

see what i'm talking about? The one in the bigger red circle? that's the only thing on the whole ECU to turn..

That's not the ECU. The ECU is located on the "transmission tunnel", just to the right of the gas pedal.