2010 Cadillac CTS Sedan AWD V6-3.0L Page 1929

2010 Cadillac CTS Sedan AWD V6-3.0L Page 1929

* 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 P2232

- HO2S Signal Circuit Shorted to Heater Circuit Bank 1 Sensor 2

DTC P2235

- HO2S Signal Circuit Shorted to Heater Circuit Bank 2 Sensor 2

Circuit Description

The engine control module (ECM) supplies a voltage near 450 mV between the heated oxygen sensor (HO2S) signal circuit and the low reference

circuit. The HO2S varies the voltage over a range from about 1,000 mV when the exhaust is rich, down through about 10 mV when the exhaust is

lean. The ECM monitors and stores the HO2S voltage information. The ECM evaluates the HO2S voltage samples in order to determine the amount

of time that the HO2S voltage was out of range. Or, to detect if the HO2S signal voltage switches at the same rate at which the ECM is

commanding the heater ON and OFF.

Conditions for Running the DTC

* The engine is operating.

* The ignition voltage is greater than 10 volts.

* The HO2S 2 is warmed up for greater than 30 seconds, greater than 90 seconds for LLT.

* The calculated exhaust gas temperature is colder than 800掳C (1,472掳F).

* The HO2S 2 heater control command is stable.

* DTC P2232 and P2235 run continuously once the conditions above exist for greater than 10 seconds.

Conditions for Setting the DTC

* The ECM detects that the HO2S signal voltage increases greater than 2 volts within 40 mS, in 4 out of 6 HO2S heater switch OFF samples.

* The condition exists for greater than 1 second, or for a cumulative of 10 seconds.

Action Taken when the DTC Sets

DTCs P2232 and P2235 are Type B DTCs.

Conditions for Clearing the MIL/DTC

DTCs P2232 and P2235 are Type B DTCs.

Diagnostic Aids

* The HO2S 2 voltage should be between 400-520 mV with the ignition ON. If the voltage is greater than the specified value, there is a

condition with the HO2S circuits. If the voltage does not change after disconnecting the HO2S 2, the condition is between the sensor and the

ECM. If the voltage is between 400-520 mV after disconnecting the sensor, the condition is with the HO2S 2.

* Inspect the HO2S harness connector for water intrusion. Moisture in a connector may cause voltage to bleed to other circuits within the

connector.

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)