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

DESCRIPTION

Tech Tips


  • Although the DTC titles say oxygen sensor, these DTCs relate to the Air-Fuel Ratio (A/F) sensor.

  • Sensor 1 refers to the sensor mounted in front of the Three-Way Catalytic Converter (TWC) and located near the engine assembly.

The A/F 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.

A000TLAE08
A000VD8E02
DTC No. DTC Detection Condition Trouble Area

P2237

P2240

Open in the circuit between terminals AF+ and AF- of the AF sensor while engine is running

(2 trip detection logic)

  • Open or short in A/F sensor (for Bank 1, 2 Sensor 1) circuit

  • A/F sensor (for Bank 1, 2 Sensor 1)

  • ECM

P2238

P2241

Any of the following conditions are met:

(2 trip detection logic)


  • AF sensor output drops while engine is running.


  • Voltage at terminal AF+ is 0.5 V or less.


  • Voltage difference between terminals AF+ and AF- is 0.1 V or less.

  • Open or short in A/F sensor (for Bank 1, 2 Sensor 1) circuit

  • A/F sensor (for Bank 1, 2 Sensor 1)

  • ECM

P2239

P2242

AF+ voltage more than 4.5 V

(2 trip detection logic)

  • Open or short in A/F sensor (for Bank 1, 2 Sensor 1) circuit

  • A/F sensor (for Bank 1, 2 Sensor 1)

  • ECM

P2252

P2255

AF- voltage 0.5 V or less

(2 trip detection logic)

  • Open or short in A/F sensor (for Bank 1, 2 Sensor 1) circuit

  • A/F sensor (for Bank 1, 2 Sensor 1)

  • ECM

P2253

P2256

AF- voltage more than 4.5 V

(2 trip detection logic)

  • Open or short in A/F sensor (for Bank 1, 2 Sensor 1) circuit

  • A/F sensor (for Bank 1, 2 Sensor 1)

  • ECM

MONITOR DESCRIPTION

These DTCs are output when there is an open or short in the A/F sensor circuit, or if A/F sensor output drops. To detect these problems, the voltage of the A/F sensor is monitored when turning the power 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 A/F 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 A/F 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.

CAUTION / NOTICE / HINT

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.

  • When viewed from the rear of the engine assembly, Bank 1 is on the left side and Bank 2 is on the right side.

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (A/F SENSOR - ECM)


    1. Turn the power switch off.

      A000TXDE04

    2. Disconnect the E3 and E4 ECM connectors.

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

      Standard resistance (Check for open)
      Tester Connection Condition Specified Condition
      E47-1 (HA1A) - E3-5 (HA1A) Always Below 1 Ω
      E48-1 (HA2A) - E3-6 (HA2A) Always Below 1 Ω
      E3-4 (E04) - Body ground Always Below 1 Ω
      E4-1 (E05) - Body ground Always Below 1 Ω
      Standard resistance (Check for short)
      Tester Connection Condition Specified Condition
      E47-1 (HA1A) or E3-5 (HA1A) - Body ground Always 10 kΩ or higher
      E48-1 (HA2A) or E3-6 (HA2A) - Body ground Always 10 kΩ or higher

    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. CHECK WHETHER DTC OUTPUT RECURS


    1. Put the engine in inspection mode Click here.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the tester ON.

    4. Clear the DTCs Click here.

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

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

    7. Read pending DTCs.

      Result
      Display (DTC Output) Proceed to
      No output A
      P2237, P2240, P2238, P2241, P2239, P2242, P2252, P2255, P2253 or P2256 B

    A

    END

    B

    REPLACE ECM Click here