Suzuki Engine 2002 GRAND VITARA SQ625, Service Manual

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ENGINE GENERAL INFORMATION AND DIAGNOSIS (G16/J20 ENGINES) 6-97
TROUBLESHOOTING (DTC P0400)
Step Action Yes No
1 Was “Engine Diag. Flow Table” performed? Go to Step 2. Go to “Engine Diag.
Flow Table”.
2 Is there DTC P0403 (EGR circuit malfunction)? Go to DTC P0403 Diag. Flow
Table.
Go to Step 3.
3 Do you have SUZUKI scan tool? Go to Step 4. Go to Step 6.
4 EGR Valve Operation Check :
1) With ignition switch OFF, install SUZUKI
scan tool.
2) Check EGR system referring to “EGR Sys-
tem” in Section 6E1.
Is it in good condition?
Go to Step 5. Go to Step 6.
5 MAP Sensor Check :
1) Check MAP sensor for performance refer-
ring to “Manifold Absolute Pressure (MAP)
Sensor” in Section 6E1.
Is check result satisfactory?
Intermittent trouble or faulty
ECM (PCM). Check for inter-
mittent referring to “Intermit-
tent and Poor Connection” in
Section 0A. Repair or replace.
6 EGR Valve Power Supply Circuit Check :
1) With ignition switch OFF, disconnect EGR
valve coupler.
2) With ignition switch ON, check voltage
between C04-2 (“BLU/BLK” wire terminal of
EGR valve coupler) and ground, C04-5
(“BLU/BLK” wire terminal of EGR valve cou-
pler) and ground.
Is each voltage 10 – 14 V?
Go to Step 7. Faulty “BLU/BLK” wire.
7 EGR Valve Stepper Motor Coil Circuit Check :
1) With ignition switch OFF, connect EGR
valve coupler and disconnect ECM (PCM)
couplers.
2) Check resistance between C51-3-4 and
C51-2-13, C51-2-14, C51-2-15, C51-2-16.
Is each resistance 20 – 24
Ω
at 20°C, 68°F?
Go to Step 8. Faulty “LT GRN”, “LT
GRN/WHT”, “LT GRN/
YEL”, “LT GRN/RED”
wire or EGR valve.
8 MAP Sensor Check :
1) Check MAP sensor for performance refer-
ring to “Manifold Absolute Pressure (MAP)
Sensor” in Section 6E1.
Is check result satisfactory?
EGR passage clogged or
EGR valve malfunction.
If all above are OK, intermit-
tent trouble or faulty ECM
(PCM).
Check for intermittent refer-
ring to “Intermittent and Poor
Connection” in Section 0A. Repair or replace.