2010 Cadillac Truck SRX FWD V6-3.0L Page 1301

2010 Cadillac Truck SRX FWD V6-3.0L Page 1301

* 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 (LAU) (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)Engine Controls Schematics

(LF1) (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)

Connector End View Reference

Component Connector End Views (See: Diagrams/Connector Views/Connector End Views By Name)

Electrical Information Reference

* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit

Testing/Circuit Testing)

* Troubleshooting with a Test Lamp (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic

Procedures/Circuit Testing/Troubleshooting with a Test Lamp)