As I was passing a vehicle all of these things happened at once.
Check engine light on, key light on, tranny stuck in OD, engine runs rough unless you barely give it gas, tachometer quit working, and I'm sure I'm missing some things.
I changed the ECM but then the car wouldn't start at all. Don't know if it was a bad ECM or that's not the problem.

 

Could be a loose / bad ECU ground under the hood, where several small black wires attach to the engine. On older models that was at the thermostat, but I think the 2001 will be different.

 

so what codes were given ???

 

No codes available. We tried on 3 different code readers (autozone), and 2 different models of snap~on readers and they all said "unable to connect".

 

When you say it won't start, do you mean that it cranks but it won't fire? Because if the battery has run down (due to charging system failure) you will get all the lights coming on, rough running, etc.-- but then when you try to re-start, the battery is too dead to turn the starter.

 

usually when you are unable to connect that means the ECU is fried

 

It'll turn over fine, but it won't start. Then I disconnected battery and plugged the old ECM back in and it started but run like crap with the same old problems. The ECM I bought is used, so who knows if it's even good. Do I need to have a code reader hooked up to clear anything for the "newer" ECM to work?

 

remember these cars are equipped with an engine immobilizer system so using the new ECU won't start the engine until the key's are re-programmed. it will turn over but won't start. the only place that will re-program is a honda dealer or speciality lock smith.