2010 Cadillac Truck Escalade RWD V8-6.0L Hybrid Page 2884

2010 Cadillac Truck Escalade RWD V8-6.0L Hybrid Page 2884

* 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 P2270

- HO2S Signal Stuck Lean Bank 1 Sensor 2

DTC P2272

- HO2S Signal Stuck Lean Bank 2 Sensor 2

Diagnostic Fault Information

Typical Scan Tool Data

Circuit/System Description

The heated oxygen sensors (HO2S) are used for fuel control and catalyst monitoring. Each HO2S compares the oxygen content of the surrounding

air with the oxygen content of the exhaust stream. When the engine is started, the control module operates in an Open Loop mode, ignoring the

HO2S signal voltage while calculating the air-to-fuel ratio. While the engine runs, the HO2S heats up and begins to generate a voltage within a

range of 0-1,275 mV. Once sufficient HO2S voltage fluctuation is observed by the control module, Closed Loop is entered. The control module

uses the HO2S voltage to determine the air-to-fuel ratio. An HO2S voltage that increases toward 1,000 mV indicates a rich fuel mixture. An HO2S

voltage that decreases toward 0 mV indicates a lean fuel mixture.

The heating elements inside each HO2S heat the sensor to bring the sensor up to operating conditions faster. This allows the system to enter Closed

Loop earlier and the control module to calculate the air-to-fuel ratio sooner.

Conditions for Running the DTC

* DTCs P0036, P0037, P0038, P0137, P0138, P0140, P0141, P0443, P0458, P0459, P2232 are not set.

* The ignition 1 voltage is between 10-18 volts.

* The engine run time is greater than 5 minutes.

* The engine speed is between 1,100-2,500 RPM.

* The mass air flow (MAF) is between 3-20 g/s.

* The vehicle speed is between 50-120 km/h (31-75 mph).

* The fuel level is greater than 10 percent.

* The fuel system is in Closed Loop.

* The catalytic converter temperature is between 550-900掳C (1,022-1,652掳F).

* The DTCs run once per ignition cycle when the above conditions are met.

Conditions for Setting the DTC

P2270

The ECM does not detect a HO2S voltage greater than 805 mV before accumulated mass air flow exceeds 550 grams.