2010 Cadillac CTS Sedan AWD V6-3.6L Page 1946
瀚慖f less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal,
replace the K20 ECM.
瀚慖f greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
4. Verify the scan tool BARO Sensor parameter is less than 1 kPa (0.2 psi).
瀚慖f greater than the specified range, test the signal circuit terminal 3 for a short to voltage. If the circuit tests normal, replace the K20 ECM.
5. Install a 3 A fused jumper wire between the signal circuit terminal 3 and the 5 V reference circuit terminal 1. Verify the scan tool BARO
Sensor parameter is greater than 127 kPa (18.4 psi).
瀚慖f less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace
the K20 ECM.
6. If the circuits test normal, replace the B17 BARO sensor.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Barometric Pressure Sensor Replacement (LF1) ()
* Control Module References (See: Testing and Inspection/Programming and Relearning) for engine control module replacement, setup, and
programming
P2232
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.
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
