Suzuki WagonR+ RB310 Service Manual page 670

Troubleshooting
Step
1 Was "Engine and Emission Control System
Check" performed?
2 Check HO2S–1 heater power circuit.
1) Disconnect connector from HO2S–1 sen-
sor with ignition switch turned OFF.
2) Check for proper connection to HO2S–1
sensor at "BLK/WHT" and "YEL" wire termi-
nals.
3) If wire and connection are OK, measure
voltage between "BLK/WHT" wire terminal
and engine ground with ignition switch
turned ON.
Is voltage over 10 V?
3 Check HO2S–1 heater power circuit.
1) Disconnect connectors from ECM with igni-
tion switch turned OFF.
2) Measure resistance between "BLK/WHT"
wire terminal of HO2S–1 connector and
"E21-28" terminal wire of ECM connector.
Is resistance below 5
4 Check HO2S–1 heater drive circuit.
1) Measure resistance between "E23-4" wire
terminal of ECM connector and vehicle
body ground.
Is resistance infinity?
5 Check HO2S–1 heater drive circuit.
1) Turn ON ignition switch.
2) Measure voltage between "E23-4" wire ter-
minal of ECM connector and vehicle body
ground.
Is voltage 0 V?
6 Check HO2S–1 heater drive circuit.
1) Connect connector to HO2S–1 with ignition
switch turned OFF.
2) Turn ON ignition switch.
3) Measure voltage between "E23-4" wire ter-
minal of ECM connector and vehicle body
ground with disconnect connector from
ECM.
Is voltage over 10 V?
7 Check heater of sensor–1.
1) Disconnect HO2S–1 coupler with ignition
switch turned OFF.
2) Check HO2S–1 heater resistance. See Fig.
1.
It is 5.0 – 6.4 Ω
Action
Ω ?
at 20°C (68°F)?
ENGINE GENERAL INFORMATION AND DIAGNOSIS (M13 ENGINE) 6-2-99
Yes
Go to Step 2.
Go to Step 3.
Go to Step 4.
Go to Step 5.
Go to Step 6.
Go to Step 7.
Go to Step 8.
No
Go to "Engine and Emis-
sion Control System
Check" in this section.
"BLK/WHT" wire open cir-
cuit or shorted to ground
circuit.
"BLK/WHT" wire high
resistance circuit.
"YEL" wire shorted to
ground circuit.
"YEL" wire shorted to
power circuit.
"YEL" wire open circuit.
Replace HO2S–1.