I swapped a d15b vtec into a 89 hatch for a friend a few years ago and ran fine. I suggested he get a vtec controller and he decided to take it to a shop to wire in the vtec to the ecu. which is better but they but the spent 9 months doing it and now its stuck in limp mode. The check engine light is on. How do I read the codes so I can pinpoint the problem and get this car out of limp mode? Thanks in advance
