SFI SYSTEM, Diagnostic DTC:P2237, P2238, P2239, P2240, P2241, P2242, P2252, P2253, P2255, P2256

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)
P2240 Oxygen (A/F) Sensor Pumping Current Circuit / Open (Bank 2 Sensor 1)
P2241 Oxygen (A/F) Sensor Pumping Current Circuit Low (Bank 2 Sensor 1)
P2242 Oxygen (A/F) Sensor Pumping Current Circuit High (Bank 2 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)
P2255 Oxygen (A/F) Sensor Reference Ground Circuit Low (Bank 2 Sensor 1)
P2256 Oxygen (A/F) Sensor Reference Ground Circuit High (Bank 2 Sensor 1)

CAUTION / NOTICE / HINT

Tech Tips


  • Although the DTC titles say 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 (TWC) and located near the engine assembly.

DESCRIPTION

The air fuel ratio sensor, which is located between the exhaust manifold and catalyst, consists of alloyed metal elements and a heater.

Depending on the engine operating conditions, the heater heats the sensor elements to activate them. Battery voltage is applied to the heater, the sensor ground is controlled by the ECM using a duty ratio.

The sensor elements convert the oxygen concentration in the exhaust gas into voltage values to output. Based on the voltage, the ECM determines the air fuel ratio and regulates the fuel injection volume depending on the air fuel ratio and engine operating conditions. The voltage changes between 0.6 V and 4.5 V while the engine is running. If the air fuel ratio is lean, which means the oxygen concentration in the exhaust gas is high, the voltage is high. If the air fuel ratio is rich, which means the oxygen concentration in the exhaust gas is low, the voltage is low.

A015YTYE40
A0161LRE01
DTC No. DTC Detection Condition Trouble Area

P2237

P2240

Open in the circuit between terminals A1A+ (A1A-) and A1A- (A2A-) of the air fuel ratio sensor while engine is running

(2 trip detection logic)

  • Open in air fuel ratio sensor (bank 1, 2 sensor 1) circuit

  • Air fuel ratio sensor (bank 1, 2 sensor 1)

  • ECM

P2238

P2241

Any of the following conditions are met

(2 trip detection logic)


  • Air fuel ratio sensor output drops while engine is running.


  • Voltage at terminal A1A+ (A1A-) is 0.5 V or less.


  • Voltage difference between terminals A1A+ (A1A-) and A1A- (A2A-) is 0.1 V or less.

  • Open or short in air fuel ratio sensor (bank 1, 2 sensor 1) circuit

  • Air fuel ratio sensor (bank 1, 2 sensor 1)

  • ECM

P2239

P2242

A1A+ (A2A+) voltage is more than 4.5 V

(2 trip detection logic)

  • Open or short in air fuel ratio sensor (bank 1, 2 sensor 1) circuit

  • Air fuel ratio sensor (bank 1, 2 sensor 1)

  • ECM

P2252

P2255

A1A- (A2A-) voltage is 0.5 V or less

(2 trip detection logic)

  • Open or short in air fuel ratio sensor (bank 1, 2 sensor 1) circuit

  • Air fuel ratio sensor (bank 1, 2 sensor 1)

  • ECM

P2253

P2256

A1A- (A2A-) voltage is more than 4.5 V

(2 trip detection logic)

  • Open or short in air fuel ratio sensor (bank 1, 2 sensor 1) circuit

  • Air fuel ratio sensor (bank 1, 2 sensor 1)

  • ECM

MONITOR DESCRIPTION

These DTCs are output when there is an open or short in the air fuel ratio sensor circuit, or if air fuel ratio sensor output drops. To detect these problems, the voltage of the air fuel ratio sensor is monitored when turning the engine switch on (IG), and the admittance (admittance is an electrical term that indicates the ease of flow of current) is checked while driving. If the voltage of the air fuel ratio sensor is between 0.6 V and 4.5 V, it is considered normal. If the voltage is out of the specified range, or the admittance is less than the standard value, the ECM will determine that there is a malfunction in the air fuel ratio sensor. If the same malfunction is detected in next driving cycle, the MIL will be illuminated and a DTC will be stored.

WIRING DIAGRAM

Refer to DTC P2195 Click here.

INSPECTION PROCEDURE

Tech Tips

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 and turn the tester ON.

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

  4. Enter the following menus: Powertrain / Engine / Active Test / Control the Injection Volume for A/F sensor.

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

  6. Monitor the output voltages of the air fuel ratio and heated oxygen sensors (AFS B1 S1 and O2S B1 S2 or AFS B2 S1 and O2S B2 S2) displayed on the intelligent 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 B1 S1 or AFS B2 S1

(Air fuel ratio)

 +25% Rich Less than 3.0 V

AFS B1 S1 or AFS B2 S1

(Air fuel ratio)

 -12.5% Lean More than 3.35 V

O2S B1 S2 or O2S B2 S2

(Heated oxygen)

 +25% Rich More than 0.55 V

O2S B1 S2 or O2S B2 S2

(Heated oxygen)

 -12.5% Lean Less than 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 A0162ADE01 A0160FEE01 A0162ADE01 A0161P9E01 -
2 A0162ADE01 A015ZP2E01 A0162ADE01 A0161P9E01

  • Air fuel ratio sensor

  • Air fuel ratio sensor heater

  • Air fuel ratio sensor circuit
3 A0162ADE01 A0160FEE01 A0162ADE01 A015ZP2E01

  • Heated oxygen sensor

  • Heated oxygen sensor heater

  • Heated oxygen sensor circuit
4 A0162ADE01 A015ZP2E01 A0162ADE01 A015ZP2E01

  • Injector

  • Fuel pressure

  • Gas leakage from exhaust system (Air-fuel ratio extremely rich or lean)

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. A0160F6E03

      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
      E42-1 (HA1A) - E6-5 (HA1A) Always Below 1 Ω
      E42-3 (A1A+) - E5-23 (A1A+) Always Below 1 Ω
      E42-4 (A1A-) - E5-22 (A1A-) Always Below 1 Ω
      E38-1 (HA2A) - E6-6 (HA2A) Always Below 1 Ω
      E38-3 (A2A+) - E5-21 (A2A+) Always Below 1 Ω
      E38-4 (A2A-) - E5-20 (A2A-) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      E42-1 (HA1A) or E6-5 (HA1A) - Body ground Always 10 kΩ or higher
      E42-3 (A1A+) or E5-23 (A1A+) - Body ground Always 10 kΩ or higher
      E42-4 (A1A-) or E5-22 (A1A-) - Body ground Always 10 kΩ or higher
      E38-1 (HA2A) or E6-6 (HA2A) - Body ground Always 10 kΩ or higher
      E38-3 (A2A+) or E5-21 (A2A+) - Body ground Always 10 kΩ or higher
      E38-4 (A2A-) or E5-20 (A2A-) - Body ground Always 10 kΩ or higher

    4. Reconnect the air fuel ratio sensor connector.

    5. Reconnect the ECM connector.


    NG

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

    OK

  2. REPLACE AIR FUEL RATIO SENSOR (BANK 1 AND/OR BANK 2)


    1. Replace the air fuel ratio sensor Click here.


    NEXT

  3. CHECK WHETHER DTC OUTPUT RECURS


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG) and turn the tester ON.

    3. Clear the DTCs Click here.

    4. Start the engine.

    5. Allow the engine to idle for 5 minutes or more.

    6. Enter the following menus: Powertrain / Engine / DTC.

    7. Read the DTCs.

      Result
      Result Proceed to
      DTC is not output A
      DTCs P2237, P2240, P2238, P2241, P2239, P2242, P2252, P2255, P2253 and/or P2256 are output B

    B

    REPLACE ECM Click here

    A

    END