Suzuki GRAND VITARA Owner's Manual page 294

1A-239 Engine General Information and Diagnosis:
Troubleshooting
NOTE
• Before performed troubleshooting, be sure to read the "Precautions of ECM Circuit Inspection: ".
• When measuring circuit voltage, resistance and/or pulse signal at ECM connector, connect the
special tool to ECM and/or the ECM connectors referring to "Inspection of ECM and Its Circuits: ".
Step
1 Fuel injector check for operating sound
1) Using sound scope, check each injector for operating
sound at engine cranking.
Do all 4 injector make operating sound?
2 Fuel injector resistance check
1) Disconnect connectors from fuel injectors with ignition
switch turned OFF.
2) Check for proper connection to fuel injector at each
terminals.
3) If OK, check all 4 fuel injectors for resistance referring to
"Fuel Injector On-Vehicle Inspection: in Section 1G".
Are all injectors in good condition?
3 Fuel injector insulation resistance check
1) Check that there is insulation between each fuel injector
terminal and engine ground.
Is there insulation?
4 Fuel injector power supply check
1) Measure voltage between each "BLU/BLK" wire terminal
of fuel injector connector and engine ground with ignition
switch turned ON.
Is voltage 10 – 14 V?
5 Wire circuit check
1) Turn OFF ignition switch.
2) Disconnect connectors from ECM.
3) Measure resistance between each "PNK", "PNK/BLK",
"PNK/GRN", "PNK/BLU" wire terminal of fuel injector
connector and vehicle body ground.
Is resistance infinity?
6 Wire circuit check
1) Measure voltage between each "PNK", "PNK/BLK",
"PNK/GRN", "PNK/BLU" wire terminal of fuel injector
connector and vehicle body ground with ignition switch
turned ON.
Is voltage 0 V?
7 Fuel injector drive signal check
1) Connect connectors to each fuel injector and ECM with
ignition switch turned OFF.
2) Turn ON ignition switch.
3) Measure voltage between each "C37-1", "C37-2", "C37-
16", "C37-17" terminal of ECM connector and vehicle
body ground.
Is voltage 10 – 14 V?
Action Yes
Fuel injectors circuit is
in good condition.
Go to Step 3.
Go to Step 4.
Go to Step 5.
Go to Step 6.
Go to Step 7.
Check fuel injector
referring to "Fuel
Injector Inspection: in
Section 1G".
If check result is
satisfactory, substitute a
known-good ECM and
recheck.
No
Go to Step 2.
Faulty fuel injector.
Faulty fuel injector.
"BLU/BLK" wire is open
or shorted to ground
circuit.
If it is in good condition,
go to "ECM Power and
Ground Circuit Check: ".
"PNK", "PNK/BLK",
"PNK/GRN" and/or
"PNK/BLU" wire(s) are
shorted to ground.
"PNK", "PNK/BLK",
"PNK/GRN" and/or
"PNK/BLU" wire(s) are
shorted to power supply
circuit.
"PNK", "PNK/BLK",
"PNK/GRN" and/or
"PNK/BLU" wire(s) are
open circuit.