P2097

DTC P2097 or P2099

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.

* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC P2097
- Post Catalyst Fuel Trim System High Limit Bank 1

DTC P2099
- Post Catalyst Fuel Trim System High Limit Bank 2

Circuit Description

Fuel trim bias is used to keep the post catalyst air/fuel ratio within a predetermined range. This allows optimal catalyst efficiency under various operating conditions. 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

* DTC P0016, P0017, P0018, P0019, P0053, P0054, P0059, P0060, P0101, P0102, P0103, P0106, P0107, P0108, P0111, P0112, P0113, P0114, P0116, P0117, P0118, P0121, P0122, P0123, P0128, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P013A, P013B, P013C, P013D, P013E, P013F, P0140, P0141, P014A, P014B, P0151, P0152, P0153, P0154, P0155, P0157, P0158, P0160, P0161, P0178, P0179, P0201, P0202, P0203, P0204, P0205, P0206, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P0301, P0302, P0303, P0304, P0305, P0306, P0340, P0341, P0345, P0346, P0365, P0366, P0390, P0391, P0442, P0443, P0446, P0449, P0452, P0453, P0455, P1153, P1221, P1248, P1249, P124A, P124B, P124C, P124D, P2147, P2148, P2150, P2151, P2153, P2154, P2156, P2157, P219A, P2227, P2228, P2229, P2230, P2269, P2270, P2271, P2272, P2273, P2440, or P2444 is not set.

* The barometric pressure (BARO) is greater than 70 kPa (10.2 PSI).

* The manifold absolute pressure (MAP) is between 0-255 kPa (0-37 PSI).

* The intake air temperature (IAT) is between -20 and +150°C (-4 and +302°F).

* The engine coolant temperature is greater than -20°C (-4°F).

* The engine is in Closed Loop status.

* The fuel control intrusive diagnostics are not active.

* DTCs P2097 and P2099 run continuously when the conditions above have been met.

Conditions for Setting the DTC

The rich correction limit for a condition causing a lean air/fuel ratio has been exceeded.

Action Taken when the DTC Sets

* DTCs P2097 and P2099 are Type B DTCs.

* The ECM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the ECM stores this information in the Failure records. If the diagnostic reports a failure on the second ignition cycle, the ECM records the operating conditions at the time of the failure. The ECM writes the operating conditions to the Freeze Frame and updates the Failure records. The ECM illuminates the malfunction indicator lamp (MIL) when one of the following occurs:

- The ECM detects the same fuel trim failure during 2 consecutive trips.

- The ECM detects any fuel trim failure during any subsequent trip if the conditions at the time of failure meet the following criteria:

* The engine load is within 20 percent of the previous test that failed.

* The engine speed is within 375 RPM of the previous test that failed.

* The engine coolant temperature is in the same range of the previous test that failed.

Conditions for Clearing the MIL/DTC

* DTCs P2097 and P2099 are Type B DTCs.

* The ECM turns OFF the malfunction indicator lamp (MIL) at the beginning of the fourth ignition cycle, after 3 ignition cycles that the diagnostic runs and does not fail.

* A current DTC, Last Test Failed, clears when the diagnostic runs and passes.

Diagnostic Aids

* It is very unlikely that an HO2S will cause this DTC to set without the occurrence of circuit related HO2S DTCs. Do not replace an HO2S to address this DTC without first performing all the steps in Circuit/System Verification.

* The post catalyst fuel trim diagnostic is very sensitive to heated oxygen sensor (HO2S) design. A non-OE sensor or an incorrect part number may cause a DTC to set.

* An exhaust system leak that may not be audible can set this DTC.

* Certain aftermarket air filters may cause a DTC to set.

* Certain aftermarket air induction systems or modifications to the air induction system may cause a DTC to set.

* Certain aftermarket exhaust system components may cause a DTC to set.

Reference Information

Schematic Reference

Engine Controls Schematics ((LFX)) [1][2]Electrical Diagrams

Connector End View Reference

Component Connector End Views Fuel Pump and Level Sensor Assembly

Electrical Information Reference

* Circuit Testing Circuit Testing

* Connector Repairs Connector Repairs

* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

* Wiring Repairs Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON, observe the scan tool DTC information. Verify there is no other HO2S or fuel trim DTC set.

• If any other HO2S or fuel trim DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.

2. Verify that none of the following conditions exist:

* Exhaust system leaks-Refer to Symptoms - Engine Exhaust Symptoms - Engine Exhaust

* Vacuum hoses for splits, kinks, and proper connections

* Insufficient fuel in the tank

* The air induction system and the air intake ducts for leaks or for a missing air filter element

* A cracked evaporative canister

* Evaporative pipes plugged, obstructed, or leaking

* The crankcase ventilation system for leaks. Refer to Crankcase Ventilation System Inspection/Diagnosis Testing and Inspection

* Engine vacuum leaks

* Low fuel system pressure-Refer to Fuel System Diagnosis Component Tests and General Diagnostics.

* Fuel that is contaminated-Refer to Alcohol/Contaminants-in-Fuel Diagnosis Testing and Inspection.

* Lean fuel injectors-Refer to Fuel Injector Solenoid Coil Test Fuel Injector Solenoid Coil Test.

• If you find any of the above conditions, repair as necessary.

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.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.