Hot Engine

Disconnect vacuum hose from EGR valve and connect vacuum gauge to hose. Push a voltmeter positive probe into the terminal at the control box connector (Pink wire). Connect the negative probe to ground.

Jack up the front of the vehicle. Support with safety stands, block rear wheels, and set hand brake. Start and warm up engine (cooling fan must come on). Vacuum and voltage should be as follows:

EGR SYSTEM TEST

Engine Condition

EGR Valve Vacuum

Pink Wire Voltage

Idle

None

Yes

Hard Acceleration ⁽¹⁾

Yes

None

4500 RPM (Blocked EGR Bleed)

Less Than 1.6-2.8 in. Hg

None

Deceleration

None

Yes

⁽¹⁾	Manual must be in second gear above 30 MPH, automatic must be in "2" position above 15 MPH.

If there is vacuum available in the first condition, check vacuum hose routing. If there are no defects, replace the EGR control valves A and B. If there is no vacuum available for the second and third condition, check for voltage at EGR control solenoid valve A (Box 1, Yellow/White wire) during the respective engine conditions.
There should be no voltage. If there is voltage, go to Troubleshooting. If there is no voltage, disconnect vacuum hose from EGR solenoid control valve A. Check for vacuum at 4500 RPM. If there is no vacuum, check vacuum lines and carburetor port. Clean and retest. If there is vacuum, replace EGR solenoid valve A and retest.
When voltage is available but vacuum is greater than 2.8 in. Hg for the third condition, replace the EGR control solenoid valve B. If there is no voltage for the first, third or fourth condition, or if there is voltage for the second condition, go to Troubleshooting.
If vacuum is available for the fourth condition, check for voltage at the EGR control solenoid valve A (Box 1, Yellow/White wire). There should be voltage during deceleration. If there is voltage, replace the EGR solenoid valve A. If there is no voltage, go to Troubleshooting.