K 1500 Truck 4WD V8-379 6.2L DSL VIN C FI (1992)
EPR Vacuum Diagnostic Chart
Test Description:
Number(s) below refer to circled number(s) on the diagnostic chart.
1. Checks for normal EPR vacuum at idle. Since electrical circuit was verified as OK on prior chart, if no vacuum is present, it is due to no source
vacuum (vacuum pump) or a restriction or leak in vacuum lines to valve, including the solenoid.
2. EPR solenoid is de-energized, so no vacuum should be present.
3. Checks for normal operation of EPR valve. When vacuum is applied, valve actuator should move and hold.
