Dtc P2096 Or P2098 - Suzuki XL7 2007 Service Manual

DTC P2096 or P2098

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 P2096: Post Catalyst Fuel Trim System Low Limit Bank 1
DTC P2098: Post Catalyst Fuel Trim System Low Limit Bank 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
HO2S 1 or 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.
Engine General Information and Diagnosis:
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.
Fuel trim bias is used by the ECM to keep the post
catalyst HO2S voltage within a range of 580-665 mV.
This allows optimal catalyst efficiency under light load
conditions, such as at idle or a steady cruise. The ECM
constantly monitors how lean or rich the fuel trim bias is
commanded, to determine if the fuel trim bias is greater
than a calibrated amount.
The HO2S utilizes the following circuits:
• A signal circuit
• A low reference circuit
• An ignition voltage circuit
• A heater control circuit
Short to Voltage
P0132
P0138
P0152
P0158
—
Open Short to Voltage
445-450 mV
445-480 mV
1A-150
Signal
Performance
P0133
P0140, P2096,
P2097
P0153
P0160, P2098,
P2099
—
1275 mV
1275 mV