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DTC P2A00

DTC P2A00

Diagnostic Instructions


• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• Diagnostic Procedure Instructions provides an overview of each diagnostic category.


DTC Descriptors

DTC P2A00 53

HO2S Circuit Closed Loop Performance Bank 1 Sensor 1 Malfunction

DTC P2A00 54

HO2S Circuit Closed Loop Performance Bank 1 Sensor 1 Malfunction

Circuit/System Description

The heated oxygen sensors (HO2S) are used for fuel control and catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the engine is started, the control module operates in an Open Loop mode, ignoring the HO2S signal voltage while calculating the air-to-fuel ratio. While the engine runs, the HO2S heats up and begins to generate a voltage within a range of 0-1,275 mV. Once sufficient HO2S voltage fluctuation is observed by the control module, Closed Loop is entered. The control module uses the HO2S voltage to determine the air-to-fuel ratio. An HO2S voltage that increases toward 1,000 mV indicates a rich fuel mixture. An HO2S voltage that decreases toward 0 mV indicates a lean fuel mixture.

Conditions for Running the DTC


• DTCs P0106, P0107, P0108, P0116, P0117, P0118, P0131, P0132, P0201, P0202, P0203, P0204, P1516, P2101, P2119, or P2176 are not set.

• Ignition voltage is between 10-18 V

• Engine speed is between 1 000-3 400 RPM

• Airflow into the engine is between 4-30 g/s

• Engine coolant temperature (ECT) is greater than 70°C (158°F)

• Engine run time is greater than 100 s

• DTC P2A00 runs continuously when the above conditions are met for greater than 5 s


Conditions for Setting the DTC

The ECM detects that the HO2S 1 voltage is greater than 1 100 mV for greater than 20 s after closed loop is enabled.

Action Taken When the DTC Sets

DTC P2A00 is a Type B DTC

Conditions for Clearing the DTC

DTC P2A00 is a Type B DTC

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Engine Control Module Description

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 for scan tool information

Circuit/System Verification


1. Ignition ON, check the diagnostic trouble code (DTC) information with a scan tool. DTC P0030, P0053, P0131, P0132, P0134 or P0135 are not set.

2. If a DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .

3. 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

Note

You must perform the circuit/system verification before proceeding with circuit/system testing.



1. Ignition OFF, disconnect the harness connector at the B52 Heated Oxygen Sensor.

2. Ignition ON, test for 2.9 V between the B52 Heated Oxygen Sensor reference voltage circuit terminal 6 and ground

3. If less than the specified range, test the reference voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.

4. If greater than the specified range, test the reference voltage circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.

5. Test for 2.5 V between the B52 Heated Oxygen Sensor low reference circuit terminal 2 and ground.

6. If less than the specified range, test the low reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.

7. If greater than the specified range, test the low reference circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.

8. Test for 2.8 V between the B52 Heated Oxygen Sensor control circuit terminal 1 and ground.

9. If less than the specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.

10. If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.

11. Test for 2.8 V between the B52 Heated Oxygen Sensor control circuit terminal 5 and ground.

12. If less than the specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.

13. If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.

14. Ignition OFF, disconnect the X1 harness connector at the K20 Engine Control Module.

15. Test for infinite resistance between each B52 Heated Oxygen Sensor circuit terminals.

16. If less than the specified value, repair as necessary.

17. If all circuits test normal, replace the B52 Heated Oxygen Sensor and verify the DTC does not reset

18. If the DTC resets, replace the K20 Engine Control Module.


Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.


• Heated Oxygen Sensor Replacement - Sensor 1

• Control Module References for ECM replacement, setup, and programming