Suzuki 2006 SX4, Service Manual

Page: 122 / 1478

1A-78 Engine General Information and Diagnosis:
DTC P0137 / P0138: O2 Sensor (HO2S) Circuit Low Voltage / High Voltage (Sensor-2, Bank-1)
S6RW0C1104030
Wiring Diagram
Refer to “DTC P0030: HO2S Heater Control Circuit (Sensor-1, Bank-1)”.
DTC Detecting Condition and Trouble Area
DTC Confirmation Procedure
WARNING
!
• When performing a road test, select a place where there is no traffic or possibility of a traffic
accident and be very careful during testing to avoid occurrence of an accident.
• Road test should be carried out by 2 persons, a driver and a tester, on a level road.
NOTE
Check to make sure that the following conditions are satisfied when using this “DTC Confirmation
Procedure”.
• Intake air temperature at engine start: –10
°
C (14
°
F) to 80
°
C (176
°
F)
• Intake air temperature: –10
°
C (14
°
F) to 70
°
C (158
°
F)
• Engine coolant temperature: 70
°
C (158
°
F) to 150
°
C (302
°
F)
• Altitude (barometric pressure): 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more)
• The following DTCs are not detected: DTCs related to MAF sensor, ECT sensor, IAT sensor,
barometric pressure sensor, HO2S heater and VSS
1) With ignition switch turned OFF, connect scan tool.
2) Turn ON ignition switch and clear DTC using scan tool.
3) Start engine and warm up to normal operating temperature.
4) Increase vehicle speed to 60 – 80 km/h (37 – 50 mile/h) at 5th gear or D range.
5) Release accelerator pedal and with engine brake applied, keep vehicle coasting (with fuel cut for 12 sec. or more),
then stop vehicle and run engine at idle speed for 60 sec. or more.
3 A/F sensor 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, check that A/F sensor circuit is as
follows.
• Wiring harness resistance of each “Signal (+) circuit of
A/F sensor”, “Signal (–) circuit of A/F sensor”, “Control
circuit of A/F sensor heater” and “Control ground
circuit of A/F sensor heater” is less than 1
Ω
.
Are they in good condition?
Replace A/F sensor and
recheck. If this DTC is
detected again,
substitute a known-
good ECM and recheck. Repair or replace
defective wiring harness
/ connector.
Step Action Yes No
DTC detecting condition Trouble area
DTC P0137:
HO2S voltage is lower than 0.4 V for specified time while vehicle is driving
with high engine load (high speed). And HO2S max. voltage minus HO2S
min. voltage is less than 0.2 V.
(2 driving cycle detection logic)
DTC P0138:
HO2S voltage is higher than 0.85 V for specified time while vehicle is
driving with high engine load (high speed). And HO2S max. voltage minus
HO2S min. voltage is less than 0.2 V.
(2 driving cycle detection logic)
• HO2S and/or its circuit
• Fuel system
• ECM
• Fuel shortage
• Exhaust system
• Air intake system