Buick Regal: DTC P0131, P0132, P015A, P015B, P223C, or P223E

Diagnostic Instructions

• Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle
• Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis
• An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions

DTC Descriptors

DTC P0131

HO2S Circuit Low Voltage Sensor 1

DTC P0132

HO2S Circuit High Voltage Sensor 1

DTC P015A

HO2S Delayed Response Rich to Lean Sensor 1

DTC P015B

HO2S Delayed Response Lean to Rich Sensor 1

DTC P223C

HO2S Pump Current Control Performance Bank 1 Sensor 1

DTC P223E

HO2S Reference Resistance Out of Range Bank 1 Sensor 1

Diagnostic Fault Information

Typical Scan Tool Data

HO2S 1

Circuit/System Description

The wide band heated oxygen sensor (HO2S) measures the amount of oxygen in the exhaust system and provides more information than the switching style HO2S. The wide band sensor consists of an oxygen sensing cell, an oxygen pumping cell, and a heater. The exhaust gas sample passes through a diffusion gap between the sensing cell and the pumping cell. The engine control module (ECM) supplies a voltage to the HO2S and uses this voltage as a reference to the amount of oxygen in the exhaust system. An electronic circuit within the ECM controls the pump current through the oxygen pumping cell in order to maintain a constant voltage in the oxygen sensing cell. The ECM monitors the voltage variation in the sensing cell and attempts to keep the voltage constant by increasing or decreasing the amount of current flow, or oxygen ion flow, to the pumping cell. By measuring the amount of current required to maintain the voltage in the sensing cell, the ECM can determine the concentration of oxygen in the exhaust. The HO2S voltage is displayed as a lambda value. A lambda value of 1 is equal to a stoichiometric air fuel ratio of 14.7: 1. Under normal operating conditions, the lambda value will remain around 1. When the fuel system is lean, the oxygen level will be high and the lambda signal will be high or more than 1.

When the fuel system is rich, the oxygen level will be low, and the lambda signal will be low or less than 1. The ECM uses this information to maintain the correct air/fuel ratio. If the ECM detects that the HO2S signal voltage is low, this DTC sets.

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 DTC

P0131, P0132

• DTC P0030, P0031, P0032, P0135 = Not set
• Ignition Voltage=10 to 32 V
• Engine Running
• DTCs run continuously when the above conditions are met for greater than 4 s.

P015A, P015B

• DTC P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0128, P0131, P013A, P013B, P013E, P013F, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176, P2270, P2271 = Not set
• P015A has run and passed for P015B to run.
• Ignition Voltage=10 to 32 V
• Engine Coolant Temperature=Warmer than 62ºC (144ºF)
• Intake Air Temperature=Warmer than -40ºC (-40ºF)
• Fuel Level Sensor=Greater than 10%
• Engine Run Time=Greater than 120 s
• Engine Speed=950 to 2950 RPM
• Vehicle Speed=66 to 124 km/h (41 to 77 MPH)
• Mass Air Flow=2 to 15 g/s
• Barometric Pressure=Greater than 70 kPa (10 PSI)
• Fuel Control Loop Status=Closed Loop Fuel Control
• Device controls are not active.
• The evaporative emission (EVAP) diagnostics are not in control of purge.
• HO2S 1 Heater Command=On for greater than 20 s
• After the above conditions are met for 2 s the fuel mixture is forced rich.
• At the end of the forced rich fuel state, decel fuel cut-off is active, without driver initiated accelerator pedal input.
• DTCs run once per drive cycle when the above conditions are met.

P223C

• DTC P0030, P0031, P0032, P0135 = Not set
• Ignition Voltage=10 to 32 V
• Engine Running
• The DTC runs when time in decel fuel cut-off is greater than 5 s and less than 12 s, when the above conditions are met for 7 s.

P223E

• DTC P0030, P0031, P0032, P0135 = Not set
• Ignition Voltage=10 to 32 V
• Engine Running
• DTC runs continuously when the above conditions are met for greater than 30 s.

Conditions for Setting the DTC

P0131

The engine control module detects that the heated oxygen sensor pump current or reference voltage circuit is shorted to ground for greater than 4 s.

P0132

The engine control module detects that the heated oxygen sensor pump current, reference voltage, or reference ground circuit is shorted to voltage for greater than 4 s.

P015A or P015B

The engine control module detects that the heated oxygen sensor rich-to-lean or lean-to-rich average response time is greater than a calibrated value.

The DTCs set within 60 s when the above condition is met.

P223C

The engine control module detects an open circuit fault to the pump current, reference voltage, reference ground, or trim circuit or a trim circuit short to ground, by detecting that the pump current is less than 0.10 mA or greater than 4.18 mA for greater than 7 s.

P223E

The engine control module detects that the heated oxygen sensor reference cell is colder than 700ºC (1292ºF) or warmer than 1000ºC (1832ºF) for greater than 4 s.

Actions Taken When the DTC Sets

• DTCs P0131, P0132, P223C, P223E are Type B DTCs.
• DTCs P015A, P015B are Type A DTCs.

Conditions for Clearing the DTC

• DTCs P0131, P0132, P223C, P223E are Type B DTCs.
• DTCs P015A, P015B are Type A DTCs.

Reference Information

Schematic Reference

Engine Controls Wiring Schematics (LTG)

Connector End View Reference

Component Connector End View Index

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References

Circuit/System Verification

1. Ignition - On / Vehicle - In Service Mode

2. Verify no other DTCs are set.

• If other DTCs are set

Refer to: Diagnostic Trouble Code (DTC) List - Vehicle

• Go to next step: If no other DTCs are set

3. Engine running.

4. Verify the scan tool parameter: HO2S 1=Between Lambda 0.8 and 1.1

• If not between Lambda 0.8 and 1.1

Refer to: Circuit/System Testing

• Go to next step: If between Lambda 0.8 and 1.1

5. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Verify the DTC does not set.

• If the DTC sets

Refer to: Circuit/System Testing

• Go to next step: If the DTC is not set

6. All OK.

Circuit/System Testing

NOTE: It may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference circuit continuity test can be performed.

1. Ignition/Vehicle & All vehicle systems - Off.

2. Disconnect the electrical connector: B52 Heated Oxygen Sensor.

3. Test for less than 10 ohms between the test points: Low Reference circuit terminal 1 & Ground.

• If 10 ohms or greater

1. Disconnect the electrical connector: K20 Engine Control Module
2. Test for less than 2 ohms between the test points: Low Reference circuit terminal 1@Component harness & Terminal X3 38@Control module harness
   • If 2 ohms or greater - Repair the open/high resistance in the circuit.
   • If less than 2 ohms - Test or replace the component: K20 Engine Control Module

• Go to next step: If less than 10 ohms

4. Disconnect the electrical connector: K20 Engine Control Module.

5. Test for infinite resistance between the test points: Signal circuit terminal 2@Component harness & Ground

• If less than infinite resistance

Repair the short to ground on the circuit:

• Go to next step: If infinite resistance

6. Ignition - On / Vehicle - In Service Mode.

7. Test for less than 1 V between the test points: Signal circuit terminal 2@Component harness & Ground.

• If 1 V or greater

Repair the short to voltage on the circuit:

• Go to next step: If less than 1 V

8. Ignition/Vehicle - Off.

9. Test for less than 2 ohms between the test points: Signal circuit terminal 2@Component harness & Terminal X3 36@Control module harness.

• If 2 ohms or greater - Repair the open/high resistance in the circuit.
• Go to next step: If less than 2 ohms

10. Test for infinite resistance between the test points: Signal circuit terminal 3@Component harness & Ground

• If less than infinite resistance

Repair the short to ground on the circuit:

• Go to next step: If infinite resistance

11. Ignition - On / Vehicle - In Service Mode.

12. Test for less than 1 V between the test points: Signal circuit terminal 3@Component harness & Ground

• If 1 V or greater

Repair the short to voltage on the circuit:

• Go to next step: If less than 1 V

13. Ignition/Vehicle - Off.

14. Test for less than 2 ohms between the test points: Signal circuit terminal 3@Component harness & Terminal X3 37@Control module harness.

• If 2 ohms or greater - Repair the open/high resistance in the circuit.
• Go to next step: If less than 2 ohms

15. Test for infinite resistance between the test points: Signal circuit terminal 7@Component harness & Ground

• If less than infinite resistance

Repair the short to ground on the circuit:

• Go to next step: If infinite resistance

16. Ignition - On / Vehicle - In Service Mode.

17. Test for less than 1 V between the test points: Signal circuit terminal 7@Component harness & Ground.

• If 1 V or greater

Repair the short to voltage on the circuit:

• Go to next step: If less than 1 V

18. Ignition/Vehicle - Off.

19. Test for less than 2 ohms between the test points: Signal circuit terminal 7@Component harness & Terminal X3 35@Control module harness.

• If 2 ohms or greater - Repair the open/high resistance in the circuit.
• Go to next step: If less than 2 ohms

20. Verify none of the conditions listed below exist:

• Water intrusion in the following components or their wiring harnesses: B52 Heated Oxygen Sensor
• Fuel pressure low or high. Refer to: Fuel System Diagnosis
• Contaminated or poor quality fuel. Refer to: Alcohol/Contaminants-in-Fuel Diagnosis
• Fuel saturation of the evaporative emission (EVAP) canister
• Exhaust leaks
• Engine vacuum leaks.
• Oil consumption - Refer to: Oil Consumption Diagnosis
• Coolant consumption - Refer to: Loss of Coolant
• If a condition exists

Repair as necessary

• Go to next step: If no conditions exist

21. Test or replace the component: B52A Heated Oxygen Sensor 1.

22. Perform the scan tool configuration/reset function: HO2S Heater Resistance Reset.

23. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Verify the DTC does not set.

• If the DTC sets

Test or replace the component: K20 Engine Control Module

• Go to next step: If the DTC is not set

24. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Heated Oxygen Sensor Replacement - Sensor 1
• Control Module References for ECM replacement, programming and setup

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