2010 Cadillac CTS Sedan AWD V6-3.6L Page 1195
P219B
DTC P219A or P219B (w/LF1)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/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 P0053, P0059, P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0116, P0117, P0118, P0125, P0128, P0131, P0132, P0133,
P0134, P0135, P0151, P0152, P0153, P0154, P0155, P0178, P0179, P0201-P0208, P0300, P0301-P0308, P0411, P0442, P0443, P0446,
P0449, P0452, P0453, P0455, P0496, P0606, P1133, P1153, P1516, P2101, P2135, P2176, P2269, P2440, P2444, P2A00, P2A03 are not set.
* The device control is not active.
* The intrusive diagnostics are not active.
* The engine overspeed protection is not active.
* Reduced power mode, ETC DTC, is not active.
* The power take-off (PTO) is not active.
* The traction control is not active.
* The fuel control is in air-fuel Closed Loop.
* The system voltage is more than 10 V, or less than 18 V.
* The engine coolant temperature (ECT) is warmer than -20掳C (-4掳F).
* The engine speed is greater than 350 RPM, but less than 6,000 RPM.
* The mass air flow is greater than 11 g/s, but less than 510 g/s.
* Percent ethanol is less than 87 %.
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 B DTCs.
Conditions for Clearing the MIL/DTC
DTCs P219A and P219B are Type B 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 set a false DTC.
* Monitoring the misfire current counters, or misfire graph, may help to isolate the cylinder that is causing the condition.
Reference Information
Schematic Reference
Engine Controls Schematics (LLT) (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)Engine Controls Schematics
