I own 2002 Lancer Petrol & run 96,000 KMs so far. It gave exceptionelly good service. One month back, sent vehicle to local garage for preventive maintenance. After that it started showing some electrical problem like beep- beep sound even when it is totally off. Also a yellow icon on when ever I drive vehicle. It seems that cooling fan also stopped working. Mechanic said that problem is with ECM & get it tunes at show room. But we don't have any show room in Hyderabad so he made some direct wiring & fitted an external sensor to control fan movement.

Now vehicle is running fine but started consuming heavy fuel ( hardly 5 KMPL). Its emitting black smoke. Mechanic want me to replace ECM, which costs app. 40,000/-. Can some one help me?

It seems you need a better mechanic to service your vehicle properly.
You don't have to go to a dealer. I did a quick Google search for auto repairs in your area and several options came up.
You should call around and ask if they have seen the kinds of problems you're having.
Actual diagnostic trouble codes could make finding the problem easier.
Good luck!

. Check for codes using a code reader attached to the under dash data link connector.

. Read the link below to help solve the radiator fan problem:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-9.html#post1642158