1999 Honda Civic EGR Valve

  • 1999 HONDA CIVIC

Computer problem
1999 Honda Civic 4 cyl Two Wheel Drive Manual 135000 miles

I get a error code for insufficient fllow through EGR valve. I have cleaned the valve, verifed it does work electrically, cleaned ports on intake by inserting wire. At engine idle valve does not open. Red wire to solenoid shows around six volts and the yelllow/blue wire to lift sensor shows around six volts. Is valve supposed to open at idle speed? If so why isn't the solenoid getting the full 12 volts? If it doesn't open at idle when does it open? Suspect ECM not giving full voltage. Any advice?

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have the same problem?
Saturday, July 19th, 2008 AT 7:00 PM

1 Reply


DTC P0401 (D16Y5): EGR INSUFFICIENT FLOW Perform PCM reset procedure.

Connect SCS service connector.

Test drive vehicle without any electrical load.

Decelerate from 55 MPH for at least 5 seconds.

If DTC P0401 is not indicated, problem is intermittent. System is okay at this time.

If DTC P0401 is indicated, clean intake manifold EGR port with carburetor cleaner.

Also clean passage inside EGR valve with carburetor cleaner or replace valve.

NOTE: DTC P0401 is set and MIL illuminated when malfunction has been detected during 2 consecutive trips.

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Saturday, July 19th, 2008 AT 7:25 PM

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