Emission Control System: Diagnosis
DIAGNOSIS CHART
| SYMPTOM | PROBABLE CAUSE | REMEDY |
|---|---|---|
| Engine will not start or hard to start | Vacuum hose disconnected or damaged | Repair or replace |
| The EGR valve (Stepper Motor) is not closed. | Repair or replace | |
| Malfunction of the evaporative emission purge solenoid | Repair or replace | |
| Rough idle or engine stalls | The EGR valve (Stepper Motor) is not closed. | Repair or replace |
| Vacuum hose disconnected or damaged. | Repair or replace | |
| Malfunction of the positive crankcase ventilation valve | Replace | |
| Malfunction of the purge control system | Check the system; If there is a problem, check its component parts. | |
| Engine hesitates or poor acceleration | Malfunction of the exhaust gas recirculation system | Check the system; If there is a problem, check its component parts. |
| Excessive oil consumption | Positive crankcase ventilation line clogged | Check positive crankcase ventilation system |
| Poor fuel mileage | Malfunction of the exhaust gas recirculation system | Check the system; If there is a problem, check its component parts. |