how do i know if the ecu im looking at is usdm or jdm? its for a h22 p13... if that matters.

 

JDM ECU's are usually smaller and look more like a square, whereas a USDM ECU's are longer and more rectangular.

 

x2
OBD1 USDM is a rectangle and the JDM is a square.

Another way to tell is via the bar code on the side.
The bar-code will show the ECU part number, if the last three digest start with a J or a 9 it is JDM. Example 37820-P13-J01 or 37820-P13-900.

 

ok thanks guys, i had heard they were different shaped, im really just looking for a way to get by a state ref, if he looked at the jdm ecu and knew it was jdm, it would not pass, so.... guess i ll have to actually find a usdm p13

 

The USDM and JDM P13 are the same size. You can look at the numbers on the side or open it up and identify the ROM number or specific components to tell if it's JDM or USDM.

To pass the state ref you will need a USDM P13. They will not pass a JDM P13.