Suzuki Engine 2002 GRAND VITARA SQ420 Service Manual page 101

6-96 ENGINE GENERAL INFORMATION AND DIAGNOSIS (G16/J20 ENGINES)
DTC DETECTING CONDITION AND TROUBLE AREA
DTC DETECTING CONDITION
During deceleration (engine speed high with closed throttle
position) in which fuel cut is involved, difference in intake
manifold pressure between when EGR valve is opened and
when it is closed is smaller than specified value.
(2 driving cycles detection logic)
DTC CONFIRMATION PROCEDURE
WARNING:
• When performing a road test, select a place where there is no traffic or possibility of a traffic acci-
dent and be very careful during testing to avoid occurrence of an accident.
• Road test should be carried out with 2 persons, a driver and a tester, on a level road.
NOTE:
Check to make sure that the following conditions are satisfied when using this "DTC Confirmation
Procedure".
• Intake air temp. : –8°C, 18°F or higher
• Engine coolant temp. : –8 – 110°C (18 – 230°F)
• Altitude (barometric pressure) : 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more)
1) Connect scan tool to DLC with ignition switch OFF.
2) Turn ON ignition switch and clear DTC, pending DTC and freeze frame data by using scan tool and warm up
engine completely.
3) Increase vehicle speed to 55 – 60 km/h (35 – 40 mph).
4) Keep driving above vehicle speed for 7 min. or more.
5) Increase vehicle speed to 100 – 110 km/h (60 – 70 mph).
6) Release accelerator pedal and with engine brake applied, keep vehicle coasting and then stop vehicle.
7) Check if DTC and pending DTC exists by using scan tool. If not, check if EGR system monitoring test has
completed by using scan tool. If not in both of above checks (i.e., no pending DTC and EGR system monitor-
ing test not completed), check vehicle conditions (environmental) and repeat Steps 3) through 6).
TROUBLE AREA
• EGR valve
• EGR passage
• Manifold absolute pressure sensor
• ECM (PCM)