Diagnostic Instructions
DTC Descriptors
DTC P2297: HO2S Performance During Decel Fuel Cut-Off (DFCO) Sensor 1
Circuit Description
The wide band heated oxygen sensor (HO2S) measures the amount of oxygen in the exhaust system and provides more information than the switching style HO2S. The wide band sensor consists of an oxygen sensing cell, an oxygen pumping cell, and a heater. The
exhaust gas sample passes through a diffusion gap between the sensing cell and the pumping cell. The engine control module (ECM) supplies a voltage to the HO2S and uses this voltage as a reference to the amount of oxygen in the exhaust system. An electronic
circuit within the ECM controls the pump current through the oxygen pumping cell in order to maintain a constant voltage in the oxygen sensing cell. The ECM monitors the voltage variation in the sensing cell and attempts to keep the voltage constant by increasing
or decreasing the amount of current flow, or oxygen ion flow, to the pumping cell. By measuring the amount of current required to maintain the voltage in the sensing cell, the ECM can determine the concentration of oxygen in the exhaust. The HO2S voltage is
displayed as a lambda value. A lambda value of 1 is equal to a stoichiometric air fuel ratio of 14.7:1. Under normal operating conditions, the lambda value will remain around 1. When the fuel system is lean, the oxygen level will be high and the lambda signal
will be high or more than 1. When the fuel system is rich, the oxygen level will be low, and the lambda signal will be low or less than 1. The ECM uses this information to maintain the correct air/fuel ratio.
Conditions for Running the DTC
Conditions 1
| • | Before the ECM can report DTC P2297 failed, DTC P0130 must run and pass. |
| • | DTCs P0461, P0462, and P0463 are not set. |
| • | The HO2S 1 is at operating temperature. |
| • | The desired HO2S 1 is less than 1.6 lambda. |
| • | The internal ECM HO2S signal voltage is less than 4.81 volts. |
| • | The fuel injectors are enabled. |
| • | DTC P2297 runs continuously once the above conditions are met for greater than 10 seconds. |
| • | DTC P2297 runs continuously once the above conditions are met for greater than 10 minutes when the fuel level is less than 12 percent. |
Conditions 2
| • | A decel fuel cut-off has occurred 11 times with successful adjustments. |
| • | DTC P2297 runs continuously once the above condition is met. |
Conditions for Setting the DTC
Conditions 1
The ECM detects that the internal HO2S 1 signal voltage is greater than 3.7 volts for greater than 4 seconds, or for a cumulative of 50 seconds.
Conditions 2
The ECM detects that the compensation factor of the HO2S 1 is less than -25 percent or greater than 30 percent of the expected value for greater than 4 seconds, or for a cumulative of 50 seconds.
Action Taken when the DTC Sets
DTC P2297 is a Type B DTC.
Conditions for Clearing the MIL/DTC
DTC P2297 is a Type B DTC.
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
Important: Inspect the heated oxygen sensor (HO2S) for being secure before proceeding with this DTC. A sensor that is loose could cause this DTC to set.
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 are captured in the Freeze Frame/Failure Records Data List.
| ⇒ | If DTC P2297 resets, replace the HO2S 1. |
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
