Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptors
DTC P2097: Post Catalyst Fuel Trim System High LimitCircuit Description
Fuel trim bias is used to keep the post catalyst air/fuel ratio within a predetermined range. This allows optimal catalyst efficiency under light load conditions at a steady cruise. The engine control module (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.
Conditions for Running the DTC
| • | Before the ECM can report DTC P2097 failed, DTCs P0030, P0031, P0032, P0036, P0037, P0038, P0053, P0101, P0130, P0131, P0132, P0135, P0137, P0138, P0140, P0141, P167A, P2231, P2243, P2251, P2270, P2271, and P2626 must run and pass. |
| • | DTCs P0133, P2237, and P2297 are not set. |
| • | The engine is operating for greater than 2 seconds. |
| • | Closed loop fuel control is active. |
| • | DTC P2097 runs continuously once the above conditions are met for greater than 40 seconds. |
Conditions for Setting the DTC
The rich correction limit for a condition causing a lean air/fuel ratio has been exceeded for greater than 4 seconds.
Action Taken when the DTC Sets
DTC P2097 is a Type B DTC.
Conditions for Clearing the MIL/DTC
DTC P2097 is a Type B DTC.
Diagnostic Aids
| • | An HO2S will not cause this DTC to set without the occurrence of circuit related HO2S DTCs. Do not replace an HO2S to address this DTC. |
| • | An exhaust system leak that may not be audible can set this DTC. |
Reference Information
Schematic Reference
Connector End View Reference
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
- Ignition ON, observe the scan tool DTC information. Verify there is no other HO2S or fuel trim DTC set.
- Verify that the following conditions do not exist:
- 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.
| ⇒ | If any other HO2S or fuel trim DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle. |
| • | Exhaust system leaks--Refer to Exhaust Leakage |
| • | Engine vacuum leaks |
| • | Low fuel system pressure--Refer to Fuel System Diagnosis. |
| • | Fuel that is contaminated--Refer to Alcohol/Contaminants-in-Fuel Diagnosis. |
| • | Lean fuel injectors--Refer to Fuel Injector Solenoid Coil Test. |
| ⇒ | If you find any of the above conditions, repair as necessary. |
Caution: Refer to Road Test Caution in the Preface section.
Important: A road load condition is necessary to obtain closed loop.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
