HE21 - Check For EGR Flow at Idle With EGR Vacuum Connected

- Key Off.

- EGR vacuum hose connected.

- Run KOER Self-Test. Diagnostic Subroutines (DSR) - Extracting Codes

- Is KOER DTC 0402 output?

YES -- The KOER Self-Test has detected EGR flow at idle. GO to HE22. HE22 - Check EGR System Hoses For Integrity and Connection

NO -- The fault that produced DTC 0402 is intermittent. GO to HE30. HE30 - Check DPFE Sensor Output - Apply Vacuum With Hand Pump