Suzuki Grand Vitara JB627. Manual - part 57
1A-177 Engine General Information and Diagnosis:
DTC Troubleshooting
NOTE
Before this trouble shooting is performed, read the precautions for DTC troubleshooting referring to
“Precautions for DTC Troubleshooting”.
Step
Action
Yes
No
1
Was “Engine and Emission Control System Check”
performed?
Go to Step 2.
Go to “Engine and
Emission Control
System Check”.
2
A/F sensor signal check
1) Connect scan tool with ignition switch turned OFF.
2) Warm up engine to normal operating temperature and
keep it at 2000 r/min. for 60 sec.
3) Repeat racing engine (Repeat depressing accelerator
pedal 5 to 6 times continuously to enrich A/F mixture and
take foot off from pedal to enlean it).
4) Check for A/F sensor (bank-2) output current displayed
on scan tool.
Does A/F sensor output current between –0.2 mA and 0.2
mA?
Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection
Inspection in Section
00”.
Go to Step 3.
3
A/F sensor circuit check
1) Disconnect connector from A/F sensor (bank-2) and
ECM with ignition switch turned OFF.
2) Check for proper terminal connection to A/F sensor
(bank-2) connector and ECM connector.
3) If connections are OK, check that A/F sensor (bank-2)
circuit is as follows.
• Wiring harness resistance of each “Signal (+) circuit of
A/F sensor (bank-2)”, “Signal (–) circuit of A/F sensor
(bank-2)” is less than 1
Ω.
• Insulation resistance between “Signal (–) circuit of A/F
sensor (bank-2)” and vehicle body ground is infinity.
• Insulation resistance between “Signal (+) circuit of A/F
sensor (bank-2)” and “Signal (–) circuit of A/F sensor
(bank-2)” is infinity.
• Insulation resistance of wire harness is infinity
between “Signal (+) circuit of A/F sensor (bank-2)”
terminal and each other terminal at A/F sensor (bank-
2) connector.
• Insulation resistance of wire harness is infinity
between “Signal (–) circuit of A/F sensor (bank-2)”
terminal and each other terminal at A/F sensor (bank-
2) connector.
• Circuit voltage between “Signal (–) circuit of A/F
sensor (bank-2)” and vehicle body ground is 0 V with
ignition switch tuned ON.
Are they in good condition?
Go to Step 4.
Repair or replace
defective wiring
harness.
4
A/F sensor heater check
1) Check A/F sensor (bank-2) referring to “Air Fuel Ratio
(A/F) Sensor On-Vehicle Inspection in Section 1C”.
Is A/F sensor in good condition?
Substitute a known
good ECM and recheck.
If ECM OK, replace A/F
sensor (bank-2).
Replace A/F sensor
(bank-2).