2010 Cadillac CTS Sedan AWD V6-3.6L Page 919

2010 Cadillac CTS Sedan AWD V6-3.6L Page 919

Diagnostic Aids

* If the condition is intermittent, move the related harnesses and connectors, with the engine operating, while monitoring the scan tool Circuit

Test Status parameters for the component. The circuit status parameters change from OK or Not Run to Fault if there is a condition with the

circuit or a connection.

* An open fuse in the HO2S heater circuit may be caused by the heater element in one of the sensors. The condition may not be present until

the sensor operates for a period of time. If no fault is present in the heater circuit, monitor the amperage of each heater using the DMM to

determine if one of the heater elements is the cause of the open fuse. Inspect the sensor pigtail or the harness for contacting the exhaust

system.

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

* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit Testing/Circuit Testing)

* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Connector Repairs/Connector Repairs)

* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit

Testing/Testing for Intermittent Conditions and Poor Connections)

* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/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. Engine idling at operating temperature for at least 30 seconds. Observe the DTC information, DTCs P0030, P0031, P0032, P0036, P0037,

P0038, P0050, P0051, P0052, P0056, P0057, and P0058 should not set.

2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the

conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the appropriate heated oxygen sensor (HO2S).

2. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal D and ground.

Note: The ignition circuit supplies voltage to other components. Make sure you test all circuits for a short to ground or test all components

for being shorted that share the ignition circuit.

瀚慖f the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and

the ignition circuit fuse is open, test all the components connected to the ignition circuit and replace as necessary.

3. Connect a test lamp between the heater control circuit terminal C and B+. The test lamp should not illuminate.

瀚慖f the test lamp is always ON, test the control circuit for a short to ground. If the circuit/connections test normal, replace the ECM.

Note: The control circuit for the HO2S heater is pulled-up to voltage within the ECM, 2.0-3.0 volts on the control circuit is normal.

4. Idle the engine, and verify the test lamp illuminates or flashes.

瀚慖f the test lamp is always OFF, test the control circuit for an open/high resistance. If the circuit/connections test normal, replace the ECM.

5. Ignition ON, test for 2.0-3.0 V between the control circuit terminal C and ground.

瀚慖f not within the specified range, test the control circuit for a short to voltage. If the circuit/connections test normal, replace the ECM.

6. If all circuits/connections test normal, test or replace the HO2S sensor.