Cold Engine
NOTE:
Engine coolant temperature must be below thermovalve C set temperature of 158°F (70°C).
Disconnect vacuum hose 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. If vacuum is not available to EGR valve, proceed to HOT ENGINE test. If vacuum is available, replace thermovalve C and retest.