After doing research, I decided it was time to replace the hybrid battery on our 2008 Honda Civic after 14 years. The IMA light was on along with the Check Engine light and occasionally the battery light. After the battery was replaced, it was acting worse with little assist from the battery and no regenerative braking. After 60 miles the IMA light came on with the Check Engine light and strangely it seemed to act better with more assistance from the battery and regenerative braking. We took it back to the mechanic that changed the battery. He told us to get a new engine battery because it was reading under 14 volts, so we did and nothing changed. He then put in a different converter and there is no check engine or IMA light but the battery is not assisting and the car is regenerative braking. Help?!

 

Do IMA and CEL illuminate with key on, engine off (before engaging start)?