Many injuries and fatalities have been avoided in Honda Accords because of the collision switch. The collision switch senses when the vehicle may be in a crash and shuts off the fuel supply to the engine to avoid fires. However, the collision switch may be triggered by a benign impact such as a fender bender or a speed bump, making it impossible to operate the vehicle until the switch is reset. The collision switch is not a physical switch but a program written into the Accord's electronic control unit, or ECU. Try to manually reset the ECU before taking it to a professional to be reprogrammed.
Prop open the bonnet and disconnect the negative battery cable from the battery terminal with an adjustable wrench. Leave the cable disconnected overnight to allow the ECU computer to reset on its own.
Attach the battery terminal and tighten with an adjustable wrench, close the bonnet and attempt to start the vehicle. It may take a few attempts as the fuel pump primes. If the engine does not turn over, then the ECU must be removed and taken to a professional for reprogramming.
Prop open the bonnet and disconnect the negative battery terminal with an adjustable wrench.
Follow the carpet on the floor of the front passenger side of the vehicle to where the carpet and the firewall meet. Use your hands to remove the lower kick panel from the dashboard just above this area. Pull the carpet away from the firewall.
Remove the retaining bolts on the metal bracket belt securing the ECU, the larger of the two black panels on the left. Remove the bracket belt.
Unfasten the ECU's wiring harnesses and pull the ECU out of its terminal. Take the ECU to a professional to be reset. Install the ECU back into place and reconnect the wiring harnesses.
Replace the bracket belt and tighten the retaining bolts with a socket wrench. Replace the kick panel and roll the carpet back into place. Reconnect the negative battery cable and close the bonnet.
It may take a few tries to start the vehicle as the fuel pump primes the fuel. Reprogramming the ECU requires a special computer, plug-in cables and training that only a professional would have.