Replaced my 98accord 2.3 non ulev motor with a 2002 2.3. Ulev motor. How do I go about programming the 02 ecu to Work in car. Car will not start with 2002 ecu. All I have from the 02 is key and ecu. Some things aren’t working with 98 ecu running with 02 motor. Thanks

 

Difference with 98 and 02 is how the PCM and dash wiring is differnet.
Up to '00 the dash gauges use their own sensors like the earlier 90-97 cars. The later models the gauges get the information from the PCM directly.

If all you are doing is replacing a blown '98 engine. Just use the '02 engine and transfer over all the '98-centric components and sensors.
Unless you have the key coded for the '02 PCM, it will not allow the engine to start.