2010 Cadillac CTS Sedan AWD V6-3.6L Page 1094

2010 Cadillac CTS Sedan AWD V6-3.6L Page 1094

Diagnostic Fault Information

Typical Scan Tool Data

Circuit 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. The control module supplies the HO2S with a reference, or bias voltage of about 450

mV. While the engine runs, the HO2S heats up and begins to generate a voltage within a range of 0-1,000 mV. This voltage will fluctuate above

and below the bias voltage. 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 above bias voltage toward 1,000 mV indicates a

rich fuel mixture. An HO2S voltage that decreases below bias voltage 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

* DTC P0201, P0202, P0203, P0204, P0205, P0206 P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276,

P0277, P2146, P2149, P2152, P2155, P216A, or P216D is not set.

* The ignition voltage is greater than 10 volts.

* The engine speed is greater than 240 RPM.

* The HO2S 1 heater duty cycle is greater than 90 percent for greater than 5 seconds.

* The ECM is not commanding the air/fuel mixture rich.

* DTC P0132 and P0152 run continuously once the conditions above exist for greater than 5 seconds.

Conditions for Setting the DTC

The ECM detects that an HO2S 1 signal voltage is greater than 1,150 mV.

Action Taken when the DTC Sets

DTCs P0132 and P0152 are Type B DTCs.

Conditions for Clearing the MIL/DTC

DTCs P0132 and P0152 are Type B DTCs.

Reference Information

Schematic Reference

Engine Controls Schematics (LLT) (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)

Electrical Information Reference