Accord 1985
The automatic transmission control solenoid valve is initiated when the automatic transmission lever is in position D4, D3,2 and R. In this case, the solenoid valve opens allowing vacuum into the #18 vacuum hose between the valve and the air pipe.
When the valve is initiated, between the black and yellow terminal (+) and green terminal (-) the wiring harness of the control box No. 1 must have a voltage of at least 9 V.
1. Disconnect the wiring harness from control box #1.
2. Disconnect the #18 vacuum hose from the air pipe.
3. Pump air into hose #18. Air must not pass through the valve.
4. Connect the positive battery terminal to the black terminal of the #1 control box connector and the negative battery terminal to the yellow/black 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 1986 and Prelude 1986-89
The automatic transmission control solenoid valve is activated when the automatic transmission lever is at speed, allowing air to bypass the throttle valve and providing the desired idle speed.
When the valve is initiated, between the black and yellow terminal (+) and green terminal (-) The main wiring harness of the control box must have a voltage of at least 9 V.
1. Disconnect the six-socket rectangular connector from the control box.
2. Disconnect the #23 vacuum hose from the vacuum hose manifold.
3. Vacuum hose #23. The valve must hold the vacuum. If the vacuum is not being held, replace the valve.
4. Connect the positive battery terminal to the black/yellow terminal of the control box connector and the negative terminal to the blue terminal of the connector.
5. Apply vacuum to hose #23. The valve must not hold a vacuum. If the valve is holding vacuum, replace the valve.
Accord 1987-89
1. Check the vacuum line for correct connections, kinks, blockages and disconnected hoses.
2. Warm up the engine to the optimum temperature (before turning on the cooling fan).
Set the parking brake securely.
3. Disconnect the No. 18 vacuum hose from the air pipe and connect a pressure gauge to the hose. The gauge should show vacuum.
4. If there is vacuum, go to AUTOMATIC TRANSMISSION IDLING SOLENOID CONTROL VALVE TEST #2.
5. Shift transmission to D3 or D4. The pressure gauge should indicate vacuum.
6. If there is no vacuum, go to AUTOMATIC TRANSMISSION IDLING SOLENOID CONTROL VALVE TEST #1.
Auto Transmission Idle Control Solenoid Valve Check No. 1
Accord 1987-89
1. After setting the parking brake, start the engine at idle speed.
2. Disconnect the #23 vacuum hose from the intake manifold and check for vacuum.
3. If there is no vacuum, check the vacuum port.
4. Disconnect the six-pin connector.
5. Connect the positive voltmeter lead to the black/yellow terminal and the negative lead to the green terminal.
6. Shift transmission to D3 or D4.
7. If the voltmeter shows voltage, replace the solenoid valve.
8. If there is no voltage, connect the positive probe of the voltmeter to the black/yellow terminal and the negative probe to the ground wire. Check voltage.
9. If there is no voltage, repair the break in the black and yellow wire between the solenoid valve and fuse No. 1.
10. If there is voltage, check for a break in the green wire between the solenoid valve and the computer. If the wire is intact, check the on-board computer.
Check No. 2 of the automatic transmission idle control solenoid valve
Accord 1987-89
1. With the parking brake applied, start the engine.
2. Disconnect the six-pin connector.
3. Connect the positive voltmeter lead to the black/yellow terminal and the negative lead to the green terminal.
4. If the voltmeter shows voltage - check for a short in the green wire between the solenoid valve and the computer. If the wire is in order, check the on-board computer.
5. If there is no voltage, replace the solenoid valve.