SFI SYSTEM, Diagnostic DTC:P2237, P2238, P2239, P2252, P2253

DTC Code DTC Name
P2237 Oxygen (A/F) Sensor Pumping Current Circuit / Open (Bank 1 Sensor 1)
P2238 Oxygen (A/F) Sensor Pumping Current Circuit Low (Bank 1 Sensor 1)
P2239 Oxygen (A/F) Sensor Pumping Current Circuit High (Bank 1 Sensor 1)
P2252 Oxygen (A/F) Sensor Reference Ground Circuit Low (Bank 1 Sensor 1)
P2253 Oxygen (A/F) Sensor Reference Ground Circuit High (Bank 1 Sensor 1)

DESCRIPTION

Tech Tips


  • Although the DTC titles refer to the oxygen sensor, these DTCs relate to the air fuel ratio sensor.

  • Sensor 1 refers to the sensor mounted in front of the three way catalytic converter and located near the engine assembly.

The air fuel ratio sensor generates a voltage* that corresponds to the actual air fuel ratio. This sensor voltage is used to provide the ECM with feedback so that it can control the air fuel ratio. The ECM determines the deviation from the stoichiometric air fuel ratio and regulates the fuel injection time. If the air fuel ratio sensor malfunctions, the ECM is unable to control the air fuel ratio accurately.

The air fuel ratio sensor is of the planar type and is integrated with a heater, which heats the solid electrolyte (zirconia element). This heater is controlled by the ECM. When the intake air volume is low (the exhaust gas temperature is low), a current flows into the heater to heat the sensor in order to facilitate accurate air fuel ratio detection. The heat generated by the heater is conducted to the solid electrolyte through the alumina, therefore the sensor activation is accelerated.

A three way catalytic converter is used in order to convert the carbon monoxide, hydrocarbons and nitrogen oxide into less harmful substances. To allow the three way catalytic converter to function effectively, it is necessary to keep the air fuel ratio of the engine near the stoichiometric air fuel ratio.

*: The value changes inside the ECM. Since the air fuel ratio sensor is a current output element, current is converted into a voltage inside the ECM. Any measurements taken at the air fuel ratio sensor or ECM connectors will show a constant voltage.

A0053CVE03
DTC No. DTC Detection Condition Trouble Area
P2237 An open in the circuit between terminals A1A+ and A1A- of the air fuel ratio sensor while the engine is running (2 trip detection logic).

  • Open or short in air fuel ratio sensor (Sensor 1) circuit

  • Air fuel ratio sensor (Sensor 1)

  • ECM
P2238

One of the following conditions is met (2 trip detection logic):


  • The air fuel ratio sensor output drops while the engine is running.

  • The voltage at terminal A1A+ is 0.5 V or less.

  • The voltage difference between terminals A1A+ and A1A- is 0.1 V or less.

  • Open or short in air fuel ratio sensor (Sensor 1) circuit

  • Air fuel ratio sensor (Sensor 1)

  • ECM
P2239 The A1A+ voltage is higher than 4.5 V (2 trip detection logic).

  • Open or short in air fuel ratio sensor (Sensor 1) circuit

  • Air fuel ratio sensor (Sensor 1)

  • ECM
P2252 The A1A- voltage is 0.5 V or less (2 trip detection logic).

  • Open or short in air fuel ratio sensor (Sensor 1) circuit

  • Air fuel ratio sensor (Sensor 1)

  • ECM
P2253 A1A- voltage is higher than 4.5 V (2 trip detection logic).

  • Open or short in air fuel ratio sensor (Sensor 1) circuit

  • Air fuel ratio sensor (Sensor 1)

  • ECM

WIRING DIAGRAM

Refer to DTC P0031 Click here.

CAUTION / NOTICE / HINT

Tech Tips

Intelligent tester only:

Malfunctioning areas can be identified by performing the Control the Injection Volume for A/F Sensor function provided in the Active Test. The Control the Injection Volume for A/F Sensor function can help to determine whether the air fuel ratio sensor, heated oxygen sensor and other potential trouble areas are malfunctioning.

The following instructions describe how to conduct the Control the Injection Volume for A/F Sensor operation using the intelligent tester.


  1. Connect the intelligent tester to the DLC3.

  2. Start the engine.

  3. Turn the tester on.

  4. Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.

  5. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor.

  6. Perform the Active Test operation with the engine idling (press the RIGHT or LEFT button to change the fuel injection volume.)

  7. Monitor the output voltages of the air fuel ratio sensor and heated oxygen sensor (AFS Voltage B1S1 and O2S B1S2) displayed on the tester.

Tech Tips


  • The Control the Injection Volume for A/F Sensor operation lowers the fuel injection volume by 12.5% or increases the injection volume by 25%.

  • Each sensor reacts in accordance with increases and decreases in the fuel injection volume.

Tester Display (Sensor) Injection Volume Status Voltage

AFS Voltage B1S1

(Air fuel ratio sensor)

 +25% Rich Below 3.1 V

AFS Voltage B1S1

(Air fuel ratio sensor)

 -12.5% Lean Higher than 3.4 V

O2S B1S2

(Heated oxygen sensor)

 +25% Rich Higher than 0.55 V

O2S B1S2

(Heated oxygen sensor)

 -12.5% Lean Below 0.4 V

Note

The air fuel ratio sensor has an output delay of a few seconds and the heated oxygen sensor has a maximum output delay of approximately 20 seconds.

Case

Air Fuel Ratio Sensor (Sensor 1)

Output Voltage

Heated Oxygen Sensor (Sensor 2)

Output Voltage

 Main Suspected Trouble Area
1 A0057XTE11 A0052W5E11 -
2 A0056HDE03 A0052W5E11

  • Air fuel ratio sensor

  • Air fuel ratio sensor heater

  • Air fuel ratio sensor circuit
3 A0057XTE11 A0056HDE03

  • Heated oxygen sensor

  • Heated oxygen sensor heater

  • Heated oxygen sensor circuit
4 A0056HDE03 A0056HDE03

  • Fuel pressure

  • Gas leaks from exhaust system

    (Air fuel ratio extremely lean or rich)

Tech Tips

Read freeze frame data using the intelligent tester. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR - ECM)


    1. Disconnect the air fuel ratio sensor connector.

    2. Disconnect the ECM connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      B18-3 (A1A+) - B39-103 (A1A+) Always Below 1 Ω
      B18-4 (A1A-) - B39-126 (A1A-) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      B18-3 (A1A+) or B39-103 (A1A+) - Body ground Always 10 kΩ or higher
      B18-4 (A1A-) or B39-126 (A1A-) - Body ground Always 10 kΩ or higher

    4. Reconnect the ECM connector.

    5. Reconnect the air fuel ratio sensor connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (AIR FUEL RATIO SENSOR - ECM)

    OK

  2. REPLACE AIR FUEL RATIO SENSOR


    1. Replace the air fuel ratio sensor (Sensor 1) Click here.


    NEXT

  3. CHECK WHETHER DTC OUTPUT RECURS (DTC P2237, P2238, P2239, P2252 OR P2253)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Clear the DTCs Click here.

    5. Switch the ECM from normal mode to check mode Click here.

    6. Drive the vehicle according to the Confirmation Driving Pattern.

    7. Enter the following menus: Powertrain / Engine and ECT / DTC.

    8. Read the DTCs (Pending DTCs).

      Result
      Result Proceed to
      DTC is not output A
      DTC P2237, P2238, P2239, P2252 or P2253 is output B

    A

    END

    B

    REPLACE ECM Click here