Feedback Control Solenoid Valve
- Disconnect the No. 32 vacuum hose (upper vacuum hose) from feedback control solenoid valve and plug end of vacuum hose. Connect a vacuum pump to solenoid valve. See Fig 1
.
- Warm engine to normal operating temperature. Apply vacuum. Does solenoid valve hold vacuum? If not, go to next step. If so, disconnect the 4-pin connector near solenoid valve. Does solenoid valve hold vacuum now? If so, replace solenoid valve, making sure that No. 17 vacuum hose or air cleaner port is not pinched or restricted. If solenoid valve did not hold vacuum, voltage from control unit should be inspected and corrected.
- If solenoid valve did not hold vacuum, raise engine speed to 2500 RPM and apply vacuum. Does solenoid valve hold vacuum now? If so, solenoid valve is okay. If not, disconnect 4-pin connector near solenoid valve. Measure voltage between White/Yellow (pos.) wire terminal and ground while running engine at approximately 2500 RPM.
- Is battery voltage present? If so, repair open in Black wire between control box and ground. If not, check for an open or short in White/Yellow wire between the 4-pin connector and control unit terminal B4. If wire is okay, voltage from control unit should be inspected and corrected.
Courtesy of AMERICAN HONDA MOTOR CO., INC.