Suzuki GRAND VITARA Owner's Manual page 152

1A-97 Engine General Information and Diagnosis:
Step
5 ECT sensor harness voltage check
1) Disconnect connectors from ECM with ignition switch
turned OFF.
2) Turn ON ignition switch.
3) Measure voltage between "PPL/YEL" wire terminal of
ECT sensor connector and vehicle body ground.
Is voltage about 0 V?
6 ECT sensor harness resistance check
1) Measure resistance between "C37-24" terminal of ECM
connector and "PPL/YEL" wire terminal of ECT sensor
connector with ignition switch turn OFF.
Is resistance below 3
7 ECT sensor ground circuit check
1) Connect connectors to ECM.
2) Check for proper connection of ECT sensor connector at
"GRY/GRN" wire terminal.
3) Measure resistance between "GRY/GRN" wire terminal
of ECT sensor connector and vehicle body ground.
Is resistance below 3
8 ECT sensor ground circuit check
1) Measure resistance between "C37-57" terminal of ECM
connector and vehicle body ground.
Is resistance below 3
9 ECT sensor for performance check
1) Check ECT sensor according to "Engine Coolant
Temperature (ECT) Sensor Inspection: in Section 1C".
Is it in good condition?
Action
Ω
?
Ω
?
Ω
?
Yes
Go to Step 6.
Go to Step 7.
Go to Step 9.
"GRY/GRN" wire is
open circuit or high
resistance circuit. Poor
"C37-57" connection.
Substitute a known-
good ECM and recheck.
No
"PPL/YEL" wire is
shorted to other circuit.
If wire is OK, substitute
a known-good ECM and
recheck.
"PPL/YEL" wire is high
resistance circuit.
Go to Step 8.
Faulty ECM ground
circuit. If circuit is OK,
substitute a known-
good ECM and recheck.
Replace ECT sensor.