DTC P2096 or P2097
Diagnostic Instructions
DTC Descriptors
| DTC P2096 00: Post Catalyst Fuel Trim System
Low Limit Bank 1 |
| DTC P2097 00: Post Catalyst Fuel Trim System
High Limit Bank 1 |
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
HO2S Signal
|
P0131 00, P0137 00
|
P0132 00, P0134 00, P0138 00, P0140 00
|
P0132 00, P0134 00, P0138 00
|
P0133 00, P0139 00, P2096 00, P2097 00
|
Low Reference
|
-
|
P0132 00, P0134 00, P0138 00, P0140 00
|
P0132 00, P0134 00, P0138 00, P2097 00
|
P0133 00, P0139 00, P2096 00, P2097 00
|
* Opens fuse
|
|
| |
Typical Scan Tool Data
HO2S Sensor 1 and HO2S Sensor 2
Circuit
|
Short to Ground
|
Open
|
Short to Voltage
|
Operating Conditions: Engine operating
in Closed Loop.
Normal Range: Fluctuates above and below
350-500 mV.
|
HO2S Sensor 1 and HO2S Sensor 2 Signal
|
0 V
|
400-415 mV
|
1 000 mV
|
Low Reference
|
0 V
|
400-415 mV
|
1 000 mV
|
|
| |
Circuit/System 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 engine control module (ECM) operates in
an open loop mode, ignoring the HO2S signal voltage while
calculating the air to fuel ratio. The ECM 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 ECM, closed loop is entered. The ECM 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.
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.
The HO2S utilizes the following circuits:
| • |
A low reference circuit
|
| • |
An ignition voltage
circuit |
| • |
A heater control
circuit |
Conditions for Running the DTC
| • |
The ignition voltage is
greater than 10 V. |
| • |
The barometric pressure is
greater than 72 kPa (10.44 PSI). |
| • |
The intake air temperature
(IAT) sensor parameter is less than -40°C (-40°F).
|
Conditions for Setting the DTC
Long term fuel trim adjustment has reached its limit while the
sensor voltage is still trying to move the adjustment further in
the same direction.
Action Taken When the DTC Sets
DTCs P2096 00 and P2097 00 are Type B DTCs.
Conditions for Clearing the DTC
DTCs P2096 00 and P2097 00 are Type B DTCs.
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
| 1. |
Ignition ON, observe the DTC
information with a scan tool. DTCs P0131 00, P0132 00, P0134 00,
P0137 00, P0138 00, or P0140 00 should not be set |
| 2. |
Allow the engine to reach
operating temperature. Operate the vehicle within the parameters
specified in conditions for running the DTC. These DTCs should not
set. |
| 3. |
Operate the vehicle within the
conditions for running the DTC to verify the DTC does not reset.
You may also operate the vehicle within the conditions that you
observed from the freeze frame/failure records data. |
Circuit/System Testing
| 1. |
Verify none of the following
conditions exist: |
| |
• |
Inspect the B52A Heated Oxygen
Sensor 1 and B52B Heated Oxygen Sensor 2 for being secure.
|
| |
• |
Damaged wiring between either
B52A Heated Oxygen Sensor 1 and B52B Heated Oxygen Sensor 2 and the
K20 Engine Control Module |
| |
• |
Water intrusion in the B52A
Heated Oxygen Sensor 1 and B52B Heated Oxygen Sensor 2 harness
connectors |
| |
• |
Contaminated B52A Heated
Oxygen Sensor 1 and B52B Heated Oxygen Sensor 2. |
| |
• |
Exhaust leaks near the B52A
Heated Oxygen Sensor 1 and B52B Heated Oxygen Sensor 2.
|
| ⇒ |
If you find any of the above conditions, repair as
necessary. |
| 2. |
Ignition OFF, disconnect the
harness connector at B52B Heated Oxygen Sensor 2. |
| 3. |
Ignition ON, verify the scan
tool HO2S 2 voltage parameter is between 350-550 mV. |
| ⇒ |
If less than the specified range, test the B52B
Heated Oxygen Sensor 2 high signal circuit for a short to ground.
If the circuit/connections test normal, replace the K20 Engine
Control Module. |
| 4. |
Connect the harness connector
at B52B Heated Oxygen Sensor 2. |
| 5. |
Engine idling, raise the
engine speed above 1 200 RPM for 30 s. Verify the scan tool HO2S 2
voltage parameter is greater than 60 mV. |
| ⇒ |
If less than the specified range, replace the B52B
Heated Oxygen Sensor 2. |
| 6. |
Engine idling, move the B52A
Heated Oxygen Sensor 1 and B52B Heated Oxygen Sensor 2 harnesses
between the B52A Heated Oxygen Sensor 1 and B52B Heated Oxygen
Sensor 2 harness connector and the K20 Engine Control Module.
Observe the scan tool HO2S 1 and HO2S 2 voltage parameter. Verify
neither parameter changes abruptly. |
| 7. |
If all circuits/connections
test normal, replace the B52A Heated Oxygen Sensor 1 or B52B Heated
Oxygen Sensor 2. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|
