Suzuki 2006 SX4 Service Manual page 104

1A-60 Engine General Information and Diagnosis:
DTC Troubleshooting
Step
1 Was "Engine and Emission Control System Check"
performed?
2 A/F sensor heater circuit check
1) Disconnect connector from A/F sensor with ignition
switch turned OFF.
2) Check for proper terminal connection to A/F sensor
connector.
3) If connections are OK, measure circuit voltage between
"Power supply circuit of A/F sensor heater" and vehicle
body ground with ignition switch turned ON.
Is measured voltage 10 – 14 V?
3 A/F sensor heater circuit check
1) Check that A/F sensor heater control circuit is as follows.
• Circuit voltage between "Control circuit of A/F sensor
heater" and vehicle body ground is 0 V with ignition
switch turned ON.
Is it good condition?
4 A/F sensor heater circuit check
1) Disconnect connectors form ECM and check for proper
terminal connection to ECM connector.
2) If connections are OK, check that A/F sensor heater
circuit is as follows.
• Insulation resistance of wire harness is infinity
between "Control circuit of A/F sensor heater"
terminal and each other terminal at A/F sensor
connector.
• Wiring harness resistance of "Control circuit of A/F
sensor heater" and "Control ground circuit of A/F
sensor heater" is less than 1 Ω.
• Insulation resistance between "Control circuit of A/F
sensor heater" and "Control ground circuit of A/F
sensor heater" is infinity.
Are they in good condition?
5 A/F sensor heater check
1) Check heater resistance of A/F sensor referring to "Air
Fuel Ratio (A/F) Sensor On-Vehicle Inspection in
Section 1C".
Is A/F sensor heater in good condition?
Action Yes
Go to Step 2.
Go to Step 3.
Go to Step 4.
Go to Step 5.
Substitute a known-
good ECM and recheck.
No
Go to "Engine and
Emission Control
System Check".
Repair or replace
defective wiring harness
/ connector.
Repair or replace
defective wiring harness
/ connector.
Repair or replace
defective wiring harness
/ connector.
Replace A/F sensor.