DD - Testing Notes

DESCRIPTION
The sonic Exhaust Gas Recirculation (EGR) system consists of an EGR valve position (EGRP) sensor, a normally closed, duty cycle controlled vacuum supply (EGRV) solenoid, a normally open, duty cycle controlled atmospheric pressure supply (EGRA) solenoid and an EGR valve.

The Powertrain Control Module (PCM) increases, decreases, and maintains the flow of EGR gases by activating and deactivating the two solenoids (EGRV and EGRA) at the proper time with a duty cycle signal. The response of the EGR valve to the activity of the two solenoids is detected and transmitted by the EGR Position (EGRP) sensor to the PCM.

REMEMBER
This pinpoint test is intended to diagnose only the following:

- EGRP sensor

- Harness circuits: EGRP, SIG RTN, VREF, EGRV, EGRA and VPWR

- EGRV solenoid

- EGRA solenoid

- EGR valve

- PCM

- Vacuum lines (EGRV, EGRA, EGR)


NOTE: You should enter this pinpoint test only when you have been directed here from Diagnostic Routines.