2010 Cadillac CTS Sedan AWD V6-3.0L Page 1930
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Verification
1. Ignition ON, observe the appropriate HO2S 2 voltage parameter. The HO2S 2 voltage parameter should be less than 1,050 mV.
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 HO2S 2.
2. Ignition ON, verify that the HO2S parameter is between 400-520 mV.
瀚慖f greater than the specified range, test the signal circuit of the HO2S sensor for a short to the heater circuit. If the circuit/connections test
normal, replace the ECM.
3. If all circuits/connections test normal, replace the appropriate HO2S 2.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 (LF1) (See: Powertrain Management/Computers and Control Systems/Oxygen
Sensor/Service and Repair)Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 (LLT) (See: Powertrain Management/Computers and
Control Systems/Oxygen Sensor/Service and Repair)
* Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (LF1) (See: Powertrain Management/Computers and Control Systems/Oxygen
Sensor/Service and Repair)Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (LLT) (See: Powertrain Management/Computers and
Control Systems/Oxygen Sensor/Service and Repair)
* Control Module References (See: Testing and Inspection/Programming and Relearning) for engine control module replacement, setup, and
programming
P2235
DTC P2232 or P2235
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* 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.
