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DTC P2231

DTC P2231

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 Descriptor

DTC P2231 00

HO2S Signal Circuit Shorted to Heater Circuit Sensor 1

Diagnostic Fault Information

Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performance
Heater Voltage Supply

P0030 00

P0030 00

-

P0131 5A, P0131 12

Heater Low Control

P0031 00

P0030 00

P0032 00

-

Reference Voltage (Signal)

P0131 01

P0131 12, P2243 00, P2231 00

P0131 02, P2231 00

P0133 00, P0131 52, P0131 5A, P0132 52, P0132 5B

Low Reference (Ground)

P2A00 00

P0132 02, P2243 04

P0132 02

-

Pump Current Signal

P2626 00

P2626 00

P2626 00, P2231 00

-

Trim Current Signal

P2626 00

P2626 00

P2626 00

-



Circuit/System Description

The heated broadband oxygen sensor (HO2S) measures the quantity of oxygen in the exhaust stream faster and more accurately than an HO2S of a switching type. The broadband probe consists of a oxygen detection 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 signal 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 signal voltage. The ECM monitors the voltage variation on the signal circuit and attempts to keep the voltage constant by increasing or decreasing the amount of current flow or reversing the direction of the current flow to the pumping cell. By measuring the direction and amount of current required to maintain the signal voltage, the ECM can determine the concentration of oxygen in the exhaust. The signal voltage is displayed as a lambda value. A lambda value of 1 is equal to a stoichiometric air fuel ratio of 60:1. Under normal operating conditions, the lambda value will remain around 1. When the system is lean, the oxygen level will be high and the lambda value will be high, or more than 1. When the system is rich, the oxygen level is low and the lambda value will be low, or less than 1. The ECM uses this information to maintain the proper air/fuel ratio.

Conditions for Running the DTC


• The ignition voltage is between 10-18 V.

• The engine speed is more than 80 RPM.

• The HO2S 1 heater is at operating temperature.

• DTC P2231 runs continuously when the above conditions are met.


Conditions for Setting the DTC


• The ECM detects that the HO2S 1 voltage is more than the threshold

• DTC P2231 sets within 4 s when the above condition is met continuously, or within 50 s when the above condition is met cumulatively.


Action Taken When the DTC Sets

DTC P2231 is a Type B DTC.

Conditions for Clearing the DTC

DTC P2231 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

Circuit/System Verification


1. Clear the DTCs with a scan tool.

2. Operate the vehicle within the conditions to run and set the DTC. The DTC should not be set.

3. Run the vehicle within the Conditions for Running the DTCs. You may also operate the vehicle within the conditions that you have noted 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 B52A Heated Oxygen Sensor 1.

2. Ignition ON, test for 2.9 V between the B52A Heated Oxygen Sensor 1 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 B52A Heated Oxygen Sensor 1 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 B52A Heated Oxygen Sensor 1 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 B52A Heated Oxygen Sensor 1 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 B52A Heated Oxygen Sensor 1 circuit terminals.

If less than the specified value, repair as necessary.

16. If all circuits test normal, replace the B52A Heated Oxygen Sensor 1 and verify the DTC does not reset.

17. 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