Why does my "si" ecu throw NO code, however, the ex ecu that i picked up from the pick n pull from a four door sedan throw a code 19?

 

The Si and EX engines (and possibly transmissions) are different, so the two ECUs are probably not interchangeable. Match your ECU with the engine.

 

Seriously???? I thought that the EX ecu (p28) and Si ecu (p28) are the same????

 

You may very well be right. I assumed that the ECUs would be different for the two different types of engine.

Also, does you Si have an automatic transmission (=code 19)? The ECU should be matched for both the engine and transmission.

 

RonJ, he's referring to a 92-95 Si and EX, which both have the same motor (D16Z6) and ECU (P28).

I agree with RonJ, if it is the ECU at fault for throwing the CEL, then it is probably that you are using an automatic ECU in a manual car, or vise versa.

 

Trust, thanks for the clarification. So do you think code 19 is indicating an ECU mismatch with respect to transmissions?

 

I think so, it seems that the most likely explanation is that the ECU is not matched with his transmission type.

 

thanks you guys...i need to go back to the pick n pull and confirm it...thanks!