How do i reset the computer on a chevy hhr?

You can reset the ECM on the Chevy HHR by pulling the 50 amp fuse near the battery for about 10 minutes. It's much easier than pulling the battery terminal. You can reset the ECM by pulling the 50 amp fuse near the battery for about 10 minutes. But what does the ECM actually do It essentially functions as the main computer for many of the vehicle's engine performance and drivability functions. The ECM takes the information from the engine's various sensors, and uses that information to calculate and tune engine spark and fuel for maximum power and efficiency. The average cost for engine control module (ECM) replacement is between $930 and $1,010. Labor costs are estimated between $80 and $100 while parts are priced between $850 and $910.