Epr Solenoid Electrical Circuit Check - GMC G Service Manual

6E2-18 DIESEL EMISSIONS
EPR SOLENOID ELECTRICAL CIRCUIT CH ECK
VACUUM .
FROM ^
VACUUM PUMP
EPR SOLENOID
N.C.
10 2-86
-
Circuit Description:
The EPR solenoid controls vacuum to the EPR valve.
The EPR solenoid, when energized, allows vacuum pump
vacuum to close the EPR valve and increase exhaust back
pressure, for proper EGR operation. The solenoid is sup­
plied 12 volts by the key switch and the ECM completes the
ground to energize the solenoid and turn EPR "ON".
6.2L (LH6) DIESEL
EPR VACUUM
ACTUATOR
— 439 PNK/BLK
Test Description:
Numbers below refer to circled numbers on 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 cir­
cuits to the solenoid are OK.
3. Checks for voltage or an open circuit from terminal
"B" to the ECM terminal "C12".
538 DK GRN C12
12V
FUSE
E C M
9-9-86
* 8S 3959-6E