EGR Modulator
- Disconnect modulator hoses and remove modulator. Check modulator filter for contamination or damage. Using compressed air, clean filter. Reinstall filter. Plug one of the side nozzles with a finger while blowing air into the nozzle on the other side. Check that air escapes from the air filter side of the modulator. See Fig 1 .
- Connect a vacuum gauge to nozzle No. 1 and plug nozzle No. 2 with a finger. While blowing air into nozzle No. 3, operate vacuum pump gauge and check that vacuum is applied to modulator.