Accord 1985
The idle control solenoid valve opens when the coolant temperature is below 15°C. If the coolant temperature is below the DOC, it is initiated only when the atmospheric pressure is 660 mmHg. and less. In any case, the vacuum is supplied by hose no. 18 between the solenoid valve and the air pipe. When the valve is open, between the black and yellow terminal (+) and black and blue terminal (-) of the wiring harness of the control box No. 1, a voltage of at least 9 V should be detected.
1. Disconnect the cable from control box #1.
2. Disconnect the #18 vacuum hose from the air pipe.
3. Pump air into vacuum hose #18. The valve must not let air through.
4. Connect the positive battery terminal to the black terminal of the #1 control box connector, and (-) battery terminal - to the orange terminal.
5. Disconnect the #23 vacuum hose from the intake manifold.
6. Pump air into vacuum hose #18. Air must pass through the valve.
Accord 1988 and Prelude 1988-89
The idle control solenoid valve is open when the coolant temperature is below 15°C. If the coolant temperature is below 40°C, it is initiated only if the atmospheric pressure is 660 mmHg. or less. In any case, the vacuum is supplied by hose No. 18 between the solenoid valve and the air pipe. Also, the solenoid valve opens when the vehicle speed is over 15 km/h and the engine speed is over 2000 rpm. When the valve is open, between the black and yellow terminal (+) and red-green terminal (-) the main harness of the control box must be determined by a voltage of at least 9V.
1. Disconnect the six-pin rectangular connector from the control box.
2. Disconnect the #23 vacuum hose from the vacuum hose manifold.
3. Apply vacuum to hose #23. The vacuum must be maintained. If the valve does not hold vacuum, replace the valve.
4. Connect the positive battery terminal to the black/yellow terminal of the control box connector and the negative battery terminal to the orange terminal of the connector.
5. Apply vacuum to hose #23. The valve must not hold a vacuum. If it holds, replace it.
Accord 1987-89
1. Check the vacuum line for incorrect connection, kinks, blockage and disconnection of the hoses.
2. Start the engine at idle.
3. Disconnect the #23 vacuum hose from the intake manifold and check for vacuum.
4. If no vacuum is detected, check the vacuum port.
5. Turn off the ignition.
6. Connect connector B of the cable test system (07999-PD6000A or equivalent) to main wiring harness (and not to the onboard computer).
7. Disconnect the #23 vacuum hose from the vacuum hose manifold, and connect a hand pump to the hose.
8. Apply vacuum to the hose. The vacuum must be maintained.
9. If the vacuum is not held, replace the solenoid valve.
10. Turn on the ignition and apply vacuum to the hose. The vacuum must be maintained.
11. If vacuum does not hold, repair short in red/green wire between solenoid valve and computer.
On vehicles with automatic transmission, the green wire between the automatic transmission idle solenoid valve and the on-board computer is also checked for a short circuit.
12. Connect terminal B4 to terminal A18. Apply vacuum to the hose. The vacuum must not be held.
13. If the vacuum is held - turn off the ignition. Disconnect the six-pin connector, connect the positive voltmeter probe to the black/yellow terminal and the negative probe to the red/green terminal. Turn on the ignition.
14. If there is voltage, replace the solenoid valve.
15. If there is no voltage, connect the positive voltmeter probe to the black and yellow terminal, and the negative one to the ground wire.
16. If there is no voltage, repair open in the black/yellow wire between the solenoid and the #1 fuse.
17. If there is voltage, repair the break in the red-green wire between the solenoid valve and the computer.