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)

DESCRIPTION

Tech Tips


  • Although the DTC titles say heated 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.

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 and 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 according 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.

A00O6ZME09
A00O87OE01
DTC No. DTC Detection Condition Trouble Area

P2237

P2240

 An open in the circuit between terminals A1A+/A2A+ and A1A-/A2A- of the air fuel ratio sensor while the 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):


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

  • The voltage at terminal A1A+/A2A+ is 0.5 V or less.

  • The voltage difference between terminals A1A+/A2A+ 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

 The A1A+/A2A+ voltage is higher 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

 The 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

 The A1A-/A2A- voltage is higher 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 stored when there is an open or short in the air fuel ratio sensor circuit, or if the air fuel ratio sensor output drops. To detect these problems, the voltage of the air fuel ratio sensor is monitored when turning the ignition switch to ON, and the admittance (admittance is an electrical term that indicates the ease of current flow) 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 the next driving cycle, the MIL will be illuminated and a DTC will be stored.

WIRING DIAGRAM

Refer to DTC P2195 Click here.

CONFIRMATION DRIVING PATTERN

Tech Tips


  • This confirmation driving pattern is used in the "Perform Confirmation Driving Pattern" step of the following diagnostic troubleshooting procedure.

  • Performing this confirmation driving pattern will activate the heated oxygen sensor monitor. This is useful for verifying the completion of the repair.

A00O47XE08

  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. Enter the following menus: Powertrain / Engine and ECT / Data List / O2S (A/FS) Monitor.

  7. Check that the item O2S (A/FS) Monitor displays Incmpl (incomplete).

  8. Start the engine and warm it up. (A)

  9. Drive the vehicle at between 60 km/h and 120 km/h (37 mph and 75 mph) for at least 10 minutes. (B)

  10. Note the state of the Data List items. Those items will change to Compl (complete) as the heated oxygen sensor monitor operates.

  11. On the tester, enter the following menus: Powertrain / Engine and ECT / DTC; and check if any DTCs (any pending DTCs) are output.

Tech Tips

If the item O2S (A/FS) Monitor does not change to Compl (complete) and any pending DTCs fail to be stored, extend the driving time.

INSPECTION PROCEDURE

Tech Tips

Malfunctioning areas can be identified by performing the Control the Injection Volume for air fuel ratio sensor function provided in the Active Test. The Control the Injection Volume for air fuel ratio 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. On the tester, enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor.

  5. Perform the Active Test operation with the engine idling (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 Voltage B1S1 and O2S B1S2 or AFS Voltage B2S1 and O2S B2S2) displayed on the tester.

Tech Tips


  • The Control the Injection Volume for air fuel ratio 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 or AFS Voltage B2S1

(Air fuel ratio sensor)

 +25% Rich Below 3.1 V

AFS Voltage B1S1 or AFS Voltage B2S1

(Air fuel ratio sensor)

 -12.5% Lean Higher than 3.4 V

O2S B1S2 or O2S B2S2

(Heated oxygen sensor)

 +25% Rich Higher than 0.55 V

O2S B1S2 or O2S B2S2

(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 A00O5STE01 A00O3R3E08 A00O5STE01 A00O30ZE04 -
2 A00O5STE01 A00O5QEE01 A00O5STE01 A00O30ZE04

  • Air fuel ratio sensor

  • Air fuel ratio sensor heater

  • Air fuel ratio sensor circuit
3 A00O5STE01 A00O3R3E08 A00O5STE01 A00O5QEE01

  • Heated oxygen sensor

  • Heated oxygen sensor heater

  • Heated oxygen sensor circuit
4 A00O5STE01 A00O5QEE01 A00O5STE01 A00O5QEE01

  • Fuel injector assembly

  • 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. Disconnect the air fuel ratio sensor connector.

    2. Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      C25-2 (+B) - Body ground Ignition switch ON 11 to 14 V
      C26-2 (+B) - Body ground Ignition switch ON 11 to 14 V

    4. Turn the ignition switch off.

    5. Disconnect the ECM connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      C25-1 (HA1A) - C37-17 (HA1A) Always Below 1 Ω
      C25-3 (A1A+) - C36-1 (A1A+) Always Below 1 Ω
      C25-4 (A1A-) - C36-2 (A1A-) Always Below 1 Ω
      C26-1 (HA2A) - C37-19 (HA2A) Always Below 1 Ω
      C26-3 (A2A+) - C36-7 (A2A+) Always Below 1 Ω
      C26-4 (A2A-) - C36-8 (A2A-) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      C25-1 (HA1A) or C37-17 (HA1A) - Body ground Always 10 kΩ or higher
      C25-3 (A1A+) or C36-1 (A1A+) - Body ground Always 10 kΩ or higher
      C25-4 (A1A-) or C36-2 (A1A-) - Body ground Always 10 kΩ or higher
      C26-1 (HA2A) or C37-19 (HA2A) - Body ground Always 10 kΩ or higher
      C26-3 (A2A+) or C36-7 (A2A+) - Body ground Always 10 kΩ or higher
      C26-4 (A2A-) or C36-8 (A2A-) - Body ground Always 10 kΩ or higher

    7. Reconnect the air fuel ratio sensor connector.

    8. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. REPLACE AIR FUEL RATIO SENSOR


    1. Replace the air fuel ratio sensor Click here.


    NEXT

  3. PERFORM CONFIRMATION DRIVING PATTERN


    NEXT

  4. CHECK WHETHER DTC OUTPUT RECURS


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON 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 and ECT / DTC / Pending.

    7. Read the pending DTCs.

      Result
      Result Proceed to
      No output A
      P2237, P2240, P2238, P2241, P2239, P2242, P2252, P2255, P2253 or P2256 output B

    B

    REPLACE ECM Click here

    A

    END