P219B

DTC P219A or P219B

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 P219A
- Air Fuel Imbalance Bank 1

DTC P219B
- Air Fuel Imbalance Bank 2

Circuit/System Description

The Air Fuel Imbalance diagnostic detects a rich or lean cylinder to cylinder air/fuel ratio imbalance in each bank. The diagnostic monitors the pre-catalyst heated oxygen sensor (HO2S) signal's frequency and amplitude characteristics by calculating an accumulated voltage over a predetermined sample period. An imbalance is indicated when multiple samples of the accumulated voltage are consistently higher than the desired value.

Conditions for Running the DTC

* DTCs P0016, P0017, P0018, P0019, P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0116, P0117, P0118, P0122, P0123, P0128, P0201-P0206, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P0300, P0301-P0306, P0340, P0341, P0345, P0346, P0365, P0366, P0390, P0391, P0411, P0442, P0443, P0455, P0496, P1248, P1249, P124A, P124B, P124C, P124D, P16F3, P2101, P2135, P2147, P2148, P2150, P2151, P2153, P2154, P2156, P2157, P216B, P216C, P216E, P216F, P2440, or P2444 are not set.

* The EVAP device controls and intrusive diagnostics are not active.

* The engine overspeed protection is not active.

* Engine run time is greater than 120 s.

* The engine is in Closed Loop status for greater than 5 s.

* The fuel level is greater than 10% and no fuel level sensor fault is present.

* The system voltage is greater than 11 V for greater than 0.2 s.

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

* The engine speed is between 1,600-4,000 RPM.

* The mass air flow is between 0-1,000 g/s.

Conditions for Setting the DTC

Multiple samples of the pre-catalyst HO2S accumulated voltage are consistently greater than the desired value.

Action Taken When the DTC Sets

DTCs P219A and P219B are Type A DTCs.

Conditions for Clearing the MIL/DTC

DTCs P219A and P219B are Type A DTCs.

Diagnostic Aids

* The air fuel imbalance 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.

* Monitoring the misfire current counters, or misfire graph, may help to isolate the cylinder that is causing the condition.

* 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 - Primary

Electrical Information Reference

* Circuit Testing Circuit Testing

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

* Wiring Repairs Wiring Repairs

* Connector Repairs Connector 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 Testing

1. Diagnose any other DTCs that are set. Refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.

2. With the engine idling and the transmission in the Park or Neutral position, observe the Manifold Absolute Pressure (MAP) Sensor parameter. The MAP Sensor parameter should be between 20-48 kPa (2.9-7.0 psi).

• If the MAP Sensor parameter is not between 20-48 kPa (2.9-7.0 psi), refer to DTC P0106 (LF1, LFW, or LFX) P0106 or DTC P0107 or P0108 (LF1, LFW, or LFX) P0107.

3. Inspect the air induction system for modified, damaged, leaking, or restricted components.

4. Inspect the crankcase ventilation system for improper operation.

5. Inspect the vacuum hoses for splits, kinks, and improper connections.

6. Inspect for vacuum leaks at the intake manifold, the throttle body, and the injector O-rings.

7. Test for a restricted, damaged, leaking, or modified exhaust system from the catalytic converter forward. Refer to Symptoms - Engine Exhaust Symptoms - Engine Exhaust.

8. Test the fuel injectors for improper operation. Refer to Fuel Injector Solenoid Coil Test Fuel Injector Solenoid Coil Test.

9. Test for fuel contamination. Refer to Alcohol/Contaminants-in-Fuel Diagnosis Testing and Inspection.

10. Test for excessive fuel in the crankcase due to leaking injectors.

11. Test the ignition system for improper operation. Refer to Electronic Ignition System Diagnosis Electronic Ignition (EI) System Diagnosis.

12. Test the engine for any mechanical conditions such as sticking valves, lifters, etc., which could alter the flow into the combustion chamber. Refer to Symptoms - Engine Mechanical Symptoms - Engine Mechanical.

Repair Instructions

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