EGR Vacuum Modulator

EGR vacuum modulator may be a 2-port or 3-port depending on application. On 2 port models, disconnect hoses from vacuum modulator. Plug one end of vacuum hose connection on EGR vacuum modulator.
Apply air pressure through remaining port. Air should pass freely through air filter side of modulator. On 3-port models, disconnect all hoses. Block ports "P" and "R". Apply air pressure to port "Q". See Fig 1. Air should pass through the air filter side of modulator freely.

Fig 1: Testing 3-Port Vacuum Modulator
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
On all models, operate engine at specified RPM. See EGR VACUUM MODULATOR SPECIFICATIONS table. Repeat previous test procedure in steps 1 and 2 . Strong resistance of airflow should be felt. Replace EGR vacuum modulator if resistance is not felt. Reconnect vacuum hoses to proper locations

EGR VACUUM MODULATOR SPECIFICATIONS

Application	Engine RPM
3S-FE 4-Cyl.	2500
2VZ-FE V6	3500