Suzuki GRAND VITARA Owner's Manual page 129

Step
3 MAF sensor and its circuit check
1) With ignition switch turned OFF, connect scan tool to
DLC.
2) Start engine and warm up to normal operation
temperature.
3) Check MAF value using scan tool. (Refer to "Scan Tool
Data: " for normal value.)
Is each value within specified range?
4 MAF sensor output voltage check
1) Turn OFF ignition switch.
2) Remove ECM from its bracket with ECM connectors
connected.
3) Measure voltage between "C37-26" and "C37-27"
terminals of ECM connector referring to "Mass Air Flow
(MAF) and Intake Air Temperature (IAT) Sensor On-
Vehicle Inspection: in Section 1C".
Is each value within specified range?
5 MAF sensor power supply voltage check
1) Disconnect connector from MAF and IAT sensor with
ignition switch turned OFF.
2) Turn ON ignition switch, measure voltage between
engine ground and "BLU/BLK" wire terminal (2) of MAF
and IAT sensor connector (1).
Is voltage 10 – 14 V?
6 MAF sensor ground circuit check
1) Turn OFF ignition switch, measure resistance between
"BLU" wire terminal of MAF and IAT sensor connector
and engine ground.
Is resistance below 5
7 Ground circuit check
1) Measure resistance between "C37-27" terminal of ECM
connector and vehicle body ground.
Is resistance below 5
Action
Ω
?
Ω
?
Engine General Information and Diagnosis:
Yes
Go to Step 11.
Poor "C37-26" and/or
"C37-27" terminal
connection.
If OK, substitute a
known-good ECM and
recheck.
Go to Step 6.
I4RS0A110020-01
Go to Step 8.
"BLU" wire is open or
high resistance circuit.
1A-74
No
Go to Step 4.
Go to Step 5.
"BLU/BLK" wire is open
circuit.
Go to Step 7.
ECM grounds "C37-58",
"C37-48", "C37-30",
"C37-29" and/or "C37-
15" circuit is open or
high resistance.
If wires are OK,
substitute a known-
good ECM and recheck.