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Cold Engine: Civic

  1. Disconnect vacuum hose No. 16 from EGR valve and connect vacuum gauge to hose. Start engine and raise engine speed to 4500-5000 RPM. Vacuum should not be available to EGR valve.
  2. If vacuum is not available to EGR valve, proceed to HOT ENGINE test. If vacuum is available, check for voltage at EGR control solenoid valve A or frequency solenoid valve B in emission box No. 1.
  3. There should be voltage at solenoid. If there is voltage, replace EGR solenoid valve A and retest. On 1500 HF models (except High Alt.) if there is no voltage, check the following: check control switch and thermosensor B.
  4. With ignition on, check for voltage at (Black/Yellow wire) control unit connector. There should be voltage. If there is no voltage, check fuse and wiring. Check Black wire for continuity between control unit and ground. There should be continuity.
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