Suzuki Swift Sport 2004 Service & Repair Manual page 112

1A-62 Engine General Information and Diagnosis:
Step
3 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 "BLK/RED" wire terminal of MAF and
IAT sensor connector.
Is voltage 10 – 14 V?
4 MAF sensor ground circuit check
1) Turn OFF ignition switch, measure resistance between
"GRY" wire terminal of MAF and IAT sensor connector
and engine ground.
Is resistance below 5
5 Ground circuit check
1) Remove ECM from its bracket with ECM connectors
connected.
2) Measure resistance between "C37-27" terminal of ECM
connector and engine ground.
Is resistance below 5
6 MAF sensor signal circuit check
1) Disconnect connectors from ECM with ignition switch
turned OFF.
2) Measure voltage between "GRN/BLK" wire terminal of
MAF and IAT sensor connector and engine ground with
ignition switch turned ON.
Is voltage 0 V?
7 MAF sensor signal circuit check
1) Measure resistance between "GRN/BLK" wire terminal
of MAF and IAT sensor connector and engine ground
with ignition switch turned OFF.
Is resistance infinity?
8 MAF sensor signal circuit check
1) Measure resistance between "GRN/BLK" wire terminal
of MAF and IAT sensor connector and "C37-26" terminal
of ECM connector.
Is resistance below 3
9 MAF sensor output signal check
1) Connect connectors to MAF and IAT sensor and ECM
with ignition switch turned OFF.
2) Measure voltage between "C37-26" and "C37-27"
terminals of ECM connector referring to "MAF and IAT
Sensor On-Vehicle Inspection in Section 1C".
Is each value within specified range?
Action
Ω
?
Ω
?
Ω
?
Yes
Go to Step 4.
Go to Step 6.
"GRY" wire is open or
high resistance circuit.
Go to Step 7.
Go to Step 8.
Go to Step 9.
Substitute a known-
good ECM and recheck.
No
"BLK/RED" wire is open
circuit.
Go to Step 5.
ECM grounds "E23-31",
"C37-58", "C37-15" and/
or "C37-30" circuit is
open or high resistance.
If wires are OK,
substitute a known-
good ECM and recheck.
"GRN/BLK" wire is
shorted to other circuit.
"GRN/BLK" wire is
shorted to ground
circuit.
"GRN/BLK" wire is open
or high resistance
circuit.
Faulty MAF and IAT
sensor.