Dtc P0137, P0138, P0140, P0157, P0158, Or P0160 - Suzuki XL7 2007 Service Manual

1A-95 Engine General Information and Diagnosis:

DTC P0137, P0138, P0140, P0157, P0158, or P0160

Diagnostic Instructions
• Perform the "Diagnostic System Check - Vehicle Diagnostic Information: " prior to using this diagnostic procedure.
• Review "Strategy Based Diagnosis: " for an overview of the diagnostic approach.
• "Diagnostic Procedure Instructions - Vehicle Diagnostic Information: " provides an overview of each diagnostic
category.
DTC Descriptors
DTC P0137: HO2S Circuit Low Voltage Bank 1 Sensor 2
DTC P0138: HO2S Circuit High Voltage Bank 1 Sensor 2
DTC P0140: HO2S Circuit Insufficient Activity Bank 1 Sensor 2
DTC P0157: HO2S Circuit Low Voltage Bank 2 Sensor 2
DTC P0158: HO2S Circuit High Voltage Bank 2 Sensor 2
DTC P0160: HO2S Circuit Insufficient Activity Bank 2 Sensor 2
Diagnostic Fault Information
Circuit
HO2S Bank 1 Sensor 1 Signal
HO2S Bank 1 Sensor 2 Signal
HO2S Bank 2 Sensor 1 Signal
HO2S Bank 2 Sensor 2 Signal
Low Reference
Typical Scan Tool Data
Bank 1 or 2 HO2S 2
Circuit
Operating Conditions: Engine operating in Closed Loop.
Parameter Normal Range: Fluctuates above and below 350-500 mV.
Sensor Signal
Low Reference
Circuit Description
The heated oxygen sensors (HO2S) are used for fuel
control and catalyst monitoring. Each HO2S compares
the oxygen content of the surrounding air with the
oxygen content of the exhaust stream. When the engine
is started, the control module operates in an Open Loop
mode, ignoring the HO2S signal voltage while
calculating the air-to-fuel ratio. The control module
supplies the HO2S with a reference, or bias voltage of
about 450 mV. While the engine runs, the HO2S heats
up and begins to generate a voltage within a range of 0-
1,000 mV. This voltage will fluctuate above and below
the bias voltage. Once sufficient HO2S voltage
fluctuation is observed by the control module, Closed
Loop is entered. The control module uses the HO2S
voltage to determine the air-to-fuel ratio. An HO2S
voltage that increases above bias voltage toward 1,000
mV indicates a rich fuel mixture. An HO2S voltage that
decreases below bias voltage toward 0 mV indicates a
lean fuel mixture.
Short to Open/High
Ground Resistance
P0131 P0134, P0135
P0137 P0140
P0151 P0154, P0155
P0157 P0160
P0134, P0135,
—
P0154, P0155
Short to Ground
0-60 mV
—
The heating elements inside each HO2S heat the sensor
to bring the sensor up to operating conditions faster. This
allows the system to enter Closed Loop earlier and the
control module to calculate the air-to-fuel ratio sooner.
Conditions for Running the DTCs
P0137 and P0157
• DTCs P0117, P0118, P0125, and P0128 are not set.
• The HO2S heater is at operating temperature.
• The engine is operating for greater than 1 second.
• The ignition voltage is more than 10.5 volts.
• The engine coolant temperature is less than 40°C
(104°F) at start-up and the engine coolant
temperature was more than 60°C (140°F) when the
ignition was turned OFF last ignition cycle.
• The calculated exhaust temperature is between 250-
800°C (482-1,472°F) for more than 90 seconds.
• DTCs P0137 and P0157 run continuously once the
above conditions are met.
Short to Voltage
P0132
P0138
P0152
P0158
—
Open Short to Voltage
400-455 mV
400-455 mV
Signal
Performance
P0133, P2096,
P2097
P0140
P0153, P2098,
P2099
P0160
—
1275 mV
1275 mV