ramu

Hello, I have a 1990 LS400 with 250,000 miles on it. Runs great except I can't get it won't pass the smog test. Specifically it won't pass the EGR function test. No vacuum signal is getting past the EGR modulator. I have replaced the modulator as well as the VSV. I have good signals from the throttle body vacuum ports. The alldata diagnosis tree says that the modulator is bad (new one and old one). I can't figure it out. Any suggestion would be appreciated.