Suzuki Grand Vitara Service Manual page 141

DTC Detecting Condition and Trouble Area
DTC P0401:
Difference in intake manifold absolute pressure between opened EGR valve
and closed EGR valve is smaller than specified value.
(*2 driving cycle detection logic, monitoring once / 1 driving)
DTC P0402:
Difference in intake manifold absolute pressure between opened EGR valve
and closed EGR valve is larger than specified value.
(*2 driving cycle detection logic, monitoring once / 1 driving)
DTC Confirmation Procedure
WARNING
!
• When performing a road test, select a place where there is no traffic or possibility of a traffic
accident and be very careful during testing to avoid occurrence of an accident.
• Road test should be carried out by 2 persons, a driver and a tester, on a level road.
NOTE
Check to make sure that following conditions are satisfied when using this "DTC confirmation
procedure".
• Intake air temperature at engine start: –10 °C (14 °F) to 80 °C (176 °F)
• Intake air temperature: –10 °C (14 °F) to 70 °C (158 °F)
• Engine coolant temperature: 70 °C (158 °F) to 150 °C (302 °F)
• Altitude (barometric pressure): 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more)
1) With ignition switch turned OFF, connect scan tool.
2) Turn ON ignition switch and clear DTC using scan tool.
3) Start engine and warm up to normal operating temperature.
4) Run engine at idle for 10 min.
5) Drive vehicle and increase engine speed 3000 rpm in 3rd gear.
6) Release accelerator pedal and with engine brake applied, keep vehicle coasting for 5 sec. or more. (Keep fuel cut
condition for 5 sec. or more) If fuel cut condition is not kept for 5 sec. or more, coast down a slope in engine speed
1000 – 3000 rpm for 5 sec. or more.
7) Stop vehicle and run engine at idle.
8) Check DTC and pending DTC by using scan tool.
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DTC detecting condition
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Engine General Information and Diagnosis:
• EGR valve
• EGR passage
• MAP sensor
• ECM
1A-134
Trouble area