Accord 1985-86
1. Disconnect the vacuum hose between the MAP sensor and the throttle body from the throttle body and plug the hose hole in the throttle body. Connect a hand pump to the open end of the vacuum hose.
2. Remove the sensor connector. Connect the cable test system (07999-PD6000A or equivalent) between the control unit and the cable connector.
3. Turn on the ignition. Connect the positive probe of the digital voltmeter to terminal C11 of the cable check system and the negative probe to terminal C14. Measure the voltage; it should be between 0.5V at a vacuum of 100 mmHg and 4.5V at a vacuum of 1200 mmHg.
4. If the voltage is not normal, check the vacuum hose for leaks and check the wires between the sensor and the control unit for short circuits. If the wires are OK, replace the sensor.
[The original can be found on the resource «HONDABOOK.ru»]