hey i have the second generation of b16a ( civic 1997 si ) my car is an EG6 my car work in a good condition on P08 ECU with rev limiter of 7500 RPM i've tried to install the p30 ECU which is the original ECU for the B series but the check engine pop up with code 21 and the car wont work probably. any suggest. thank you

 

That CEL code is for the Vtec Solenoid. Check your wiring.

 

checked, but why on the p08 ecu it works ?