Did an engine swap from a 2.5 to 2.2 liter engine in my 98 Outback. The "new" engine didn't have an EGR valve and now I'm getting Check Engine light coming on. My dilemna is can I "fix" this problem by changing the ECU to one that matches the "new" engine? It came out of a 2WD 5 speed Brighton and I'm told that the ECU's are transmission sensitive and manufacturer date sensitive. Tried one that was newer than mine and it didn't work at all. I'm moving in two weeks and am getting desperate because I can't pass the inspection with the Check Engine light on. Any help would be appreciated.

What ECU did you try to use?

 

I bet all the pins for the ECU weren't the same, and that's why it's not working. You need an ECU I/O diagram for your old ECU, and one from the new car to compare that the pins are the same or not. If they're not, you'll need to rewire them.

 

Last ditch effort. Put a resistor in the EGR circuit to trick the ECU. You'll have to check some manuals to see what the resistance of the EGR valve is, so you can use the correct resistor.