2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 950
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 DTCs
* Before the ECM can report that DTC P0133, DTCs P0030, P0031, P0032, and P0135 must run and pass.
* DTC P0036, P0037, P0038, P0130, P0137, P0138, P0140, P0141, P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0443, P0458,
P0459, P2096, P2097, P2177, P2178, P2179, P2787, P2088, P2089, P2090, P2232, P2235, P2270, P2271, P2272, or P2273 is not set.
* The engine speed is 1,200-3,000 RPM.
* The HO2S 1 is in Closed Loop.
* The engine load is 18-75 %.
* The exhaust gas temperature is greater than 300掳C (572掳F).
* The evaporative purge (EVAP) solenoid valve is commanded OFF or ON for greater than 10 s.
* These DTCs run continuously when the conditions above exist.
Conditions for Setting the DTCs
The ECM determines that the length of time for an HO2S 1 to switch from lean to rich and back to lean, which is called a switching cycle, has
exceeded a predetermined threshold. The condition exists for 3 cycles out of a 20 cycle test sample.
Action Taken when the DTCs Set
DTCs P0133, P013A, and P013E are Type B DTCs.
Conditions for Clearing the MIL/DTCs
DTCs P0133, P013A, and P013E are Type B DTCs.
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)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring
Repairs/Wiring Repairs)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (See: Diagnostic Trouble Code Descriptions/Powertrain Diagnostic Trouble Code
(DTC) Type Definitions)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Verification
1. Verify that other DTCs are not set.
