EPR Vacuum Check

EPR VACUUM CHECK

The EPR solenoid controls vacuum to the EPR valve. The EPR solenoid, when energized, allows engine pump vacuum to close the EPR valve. The same vacuum source is used for both the EPR and EGR solenoids. 12 volts is supplied from the ignition, and the ECM completes the ground to energize the solenoid. A vacuum leak will cause a steady "CHECK ENGINE" light after 10 seconds of engine running with the leak present. The "CHECK ENGINE" light will remain "ON" even if the vacuum leak is repaired, unless the key is shut "OFF".

Fig. 041 - Chart For EPR Vacuum Check.:

1. Checks to see if vacuum is present to EPR solenoid with the engine at idle. Normally vacuum should be present at idle.
1a. The ECM normally completes the ground to open the EPR solenoid allowing vacuum to the valve. By removing the electrical connector, the vacuum should fall to near zero.
2. Checks for a leak in the EPR valve or hoses.
3. Valve should normally move as vacuum is applied. If valve moves, fault is in solenoid or connections. VIN T, VIN V