Suzuki GRAND VITARA Owner's Manual page 174

1A-119 Engine General Information and Diagnosis:
Step
3 ECM voltage check
1) Disconnect connector from electric throttle body
assembly with ignition switch turned OFF.
2) Check for proper connection to electric throttle body
assembly at "RED", "WHT" and "GRN" wire terminals.
"BLU/YEL"
"BLU/RED"
"BLK"
3) If OK, measure voltage between "WHT" wire terminal of
electric throttle body assembly connector and engine
ground with ignition switch turned ON.
Is voltage 4 – 6 V?
4 Wire harness check
1) Disconnect connectors from ECM with ignition switch
turned OFF.
2) Check for proper connection of ECM connector at "C37-
53" terminal.
3) Measure voltage between "C37-53" terminal of ECM
connector and engine ground with ignition switch turned
ON.
Is voltage 0 V?
5 Wire harness check
1) Measure voltage between "RED" wire terminal of electric
throttle body assembly connector and engine ground
with ignition switch turned ON.
Is voltage 4 – 6 V?
6 Wire harness check
1) Turn OFF ignition switch.
2) Remove ECM from its bracket with ECM connectors
connected.
3) Check for proper connection of ECM connector at "C37-
53" and "C37-40" terminals.
4) If OK, measure voltage between "C37-40" terminal of
ECM connector and engine ground with ignition switch
turned ON.
Is voltage 4 – 6 V?
Action
For J20 engine
"RED"
"GRN"
"WHT"
"BLK"
For M16 engine
"GRN"
"RED"
"BLU/YEL"
"WHT"
"BLU/RED"
Yes
Go to Step 5.
I5JB0A110042-01
I5JB0A110043-01
Substitute a known-
good ECM and recheck.
Go to Step 9.
"RED" wire is open or
high resistance circuit.
No
Go to Step 4.
"WHT" wire is shorted to
power circuit.
Go to Step 6.
Go to Step 7.