Suzuki Grand Vitara JB416 / JB420. Manual - part 73
1A-241 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
Action
Yes
No
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?
Fuel injectors circuit is
in good condition.
Go to Step 2.
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?
Go to Step 3.
Faulty fuel injector.
3
Fuel injector insulation resistance check
1) Check that there is insulation between each fuel injector
terminal and engine ground.
Is there insulation?
Go to Step 4.
Faulty fuel injector.
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?
Go to Step 5.
“BLU/BLK” wire is open
or shorted to ground
circuit.
If it is in good condition,
go to “ECM Power and
Ground Circuit Check”.
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?
Go to Step 6.
“PNK”, “PNK/BLK”,
“PNK/GRN” and/or
“PNK/BLU” wire(s) are
shorted to ground.
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?
Go to Step 7.
“PNK”, “PNK/BLK”,
“PNK/GRN” and/or
“PNK/BLU” wire(s) are
shorted to power supply
circuit.
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?
Check fuel injector
referring to “Fuel
Injector Inspection in
Section 1G”.
If check result is
satisfactory, substitute a
known-good ECM and
recheck.
“PNK”, “PNK/BLK”,
“PNK/GRN” and/or
“PNK/BLU” wire(s) are
open circuit.