Accord 1987-89
1. Start the engine.
2. Disconnect the two-pin connector from the idle air control solenoid valve.
3. Connect the positive probe of the voltmeter to the black and yellow terminal and the negative probe to the green and black terminal.
4. Maintain the engine speed at 1500 rpm and check the voltage.
5. If there is voltage, check the green-black wire between the electromagnetic valve and the computer for a short circuit. If the wire is OK, check the on-board computer.
6. If there is no voltage, replace the solenoid valve.