EPR Solenoid Electrical Circuit Check

Circuit Description
The EPR solenoid controls vacuum to the EPR valve. The EPR solenoid, when energized, allows vacuum to close the EPR valve, this increases exhaust back pressure, for proper EGR operation. The solenoid is supplied 12 volts by the key switch and the ECM completes the ground to energize the solenoid and turn EPR "ON" when needed (EGR operation commanded).

Test Description
Number(s) below refer to circled number(s) on the diagnostic chart.
1. Checks for short to ground or a faulty ECM signal to EPR solenoid. Test light should normally be "OFF."
2. Checks for signal to energize EPR solenoid with engine at idle. If the test light is "ON," electrical circuits to the solenoid are OK.
3. Checks for voltage or an open circuit from terminal "B" to the ECM terminal "C12."