SFI SYSTEM(w/ EGR System), Diagnostic DTC:P0031,P0032,P0051,P0052,P101D and P103D

DTC Code DTC Name
P0031 Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 1 Sensor 1)
P0032 Oxygen (A/F) Sensor Heater Control Circuit High (Bank 1 Sensor 1)
P0051 Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 2 Sensor 1)
P0052 Oxygen (A/F) Sensor Heater Control Circuit High (Bank 2 Sensor 1)
P101D A/F Sensor Heater Circuit Performance Bank 1 Sensor 1 Stuck ON
P103D A/F Sensor Heater Circuit Performance Bank 2 Sensor 1 Stuck ON

DESCRIPTION

Refer to DTC P2195.

Click here

Tip:

  • 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.

  • When one of these DTCs is stored, the ECM enters fail-safe mode. The ECM turns off the air fuel ratio sensor heater in fail-safe mode. The ECM continues operating in fail-safe mode until the engine switch is turned off.

  • The ECM provides a pulse-width modulated control circuit to adjust the current through the heater. The air fuel ratio sensor heater circuit uses a relay on the +B side of the circuit.

    A164715E25

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Warning Indicate

Memory

P0031

Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 1 Sensor 1)

Air fuel ratio sensor heater current is below 0.8 A, even when the air fuel ratio sensor heater duty cycle is 50% or more (1 trip detection logic).

  • Open in air fuel ratio sensor heater circuit

  • Air fuel ratio sensor heater (for Sensor 1)

  • No. 1 integration relay

  • ECM

Comes on

DTC stored

P0032

Oxygen (A/F) Sensor Heater Control Circuit High (Bank 1 Sensor 1)

Air fuel ratio sensor heater current reaches the high limit

(Hybrid IC high current limiter port "Fail") (1 trip detection logic).

  • Short in air fuel ratio sensor heater circuit

  • Air fuel ratio sensor heater (for Sensor 1)

  • No. 1 integration relay

  • ECM

Comes on

DTC stored

P0051

Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 2 Sensor 1)

Air fuel ratio sensor heater current is below 0.8 A, even when the air fuel ratio sensor heater duty cycle is 50% or more (1 trip detection logic).

  • Open in air fuel ratio sensor heater circuit

  • Air fuel ratio sensor heater (for Sensor 1)

  • No. 1 integration relay

  • ECM

Comes on

DTC stored

P0052

Oxygen (A/F) Sensor Heater Control Circuit High (Bank 2 Sensor 1)

Air fuel ratio sensor heater current reaches the high limit

(Hybrid IC high current limiter port "Fail") (1 trip detection logic).

  • Short in air fuel ratio sensor heater circuit

  • Air fuel ratio sensor heater (for Sensor 1)

  • No. 1 integration relay

  • ECM

Comes on

DTC stored

P101D

A/F Sensor Heater Circuit Performance Bank 1 Sensor 1 Stuck ON

The heater current is higher than the specified value (1 trip detection logic).

ECM

Comes on

DTC stored

P103D

A/F Sensor Heater Circuit Performance Bank 2 Sensor 1 Stuck ON

The heater current is higher than the specified value (1 trip detection logic).

ECM

Comes on

DTC stored
Tip:

  • Bank 1 refers to the bank that includes the No. 1 cylinder.

  • Bank 2 refers to the bank that does not include the No. 1 cylinder.

  • Sensor 1 refers to the sensor closest to the engine assembly.

  • Sensor 2 refers to the sensor farthest away from the engine assembly.

MONITOR DESCRIPTION

The ECM uses information from the air fuel ratio sensor to regulate the air-fuel ratio and keep it close to the stoichiometric level. This maximizes the ability of the Three-way Catalytic Converter (TWC) to purify the exhaust gases.

The air fuel ratio sensor detects oxygen levels in the exhaust gas and transmits the information to the ECM. The inner surface of the sensor element is exposed to the outside air. The outer surface of the sensor element is exposed to the exhaust gas. The sensor element is made of platinum coated zirconia and includes an integrated heating element.

The zirconia element generates a small voltage when there is a large difference in the oxygen concentrations between the exhaust gas and outside air. The platinum coating amplifies this voltage generation.

The air fuel ratio sensor is more efficient when heated. When the exhaust gas temperature is low, the sensor cannot generate useful voltage signals without supplementary heating. The ECM regulates the supplementary heating using a duty cycle approach to adjust the average current in the sensor heater element. If the heater current is outside the normal range, the signal transmitted by the air fuel ratio sensor becomes inaccurate. As a result, the ECM is unable to regulate the air-fuel ratio properly.

When the current in the air fuel ratio sensor heater is outside the normal operating range, the ECM interprets this as a malfunction in the sensor heater and stores a DTC.

MONITOR STRATEGY

Frequency of Operation

Continuous

TYPICAL ENABLING CONDITIONS

Table 1. P0031 and P0051

Air fuel ratio sensor heater duty cycle

50% or more
Table 2. P0032 and P0052

Air fuel ratio sensor heater duty cycle

More than 0%
Table 3. P101D and P103D

Air fuel ratio sensor heater duty cycle

10 to 60%

Air fuel ratio sensor heater ON current

0.8 A or higher
Tip:

Refer to "Data List / Active Test" [A/F Heater Duty #1, A/F Heater Duty #2] (Click here).

CONFIRMATION DRIVING PATTERN

A198819E51

  1. Connect the intelligent tester to the DLC3.

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

  3. Clear DTCs (even if no DTCs are stored, perform the clear DTC operation).

  4. Turn the engine switch off and wait for at least 30 seconds.

  5. Turn the engine switch on (IG) and turn the tester on [A].

  6. Start the engine and idle it for 5 minutes or more [B].

  7. With the vehicle stationary, depress the accelerator pedal and maintain an engine speed of 3000 rpm for 1 minute [C].

  8. Idle the engine for 5 minutes or more [D].

  9. Enter the following menus: Powertrain / Engine and ECT / DTC [E].

  10. Read the pending DTCs.

    Tip:

    • If a pending DTC is output, the system is malfunctioning.

    • If a pending DTC is not output, perform the following procedure.

  11. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

  12. Input the DTC: P0031, P0032, P0051, P0052, P101D or P103D.

  13. Check the DTC judgment result.

    Tester Display

    Description

    NORMAL

    • DTC judgment completed

    • System normal

    ABNORMAL

    • DTC judgment completed

    • System abnormal

    INCOMPLETE

    • DTC judgment not completed

    • Perform driving pattern after confirming DTC enabling conditions

    UNKNOWN

    • Unable to perform DTC judgment

    • Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit
    Tip:

    • If the judgment result shows NORMAL, the system is normal.

    • If the judgment result shows ABNORMAL, the system has a malfunction.

    • If the judgment result shows INCOMPLETE or UNKNOWN, perform steps [B] through [E] again.

WIRING DIAGRAM

Refer to DTC P2195.

Click here

CAUTION / NOTICE / HINT

Note:

Inspect the fuses of circuits related to this system before performing the following inspection procedure.

Tip:

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. INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)

    1. Inspect the air fuel ratio sensor.

      Click here

      Result

      Result

      OK

      NG
    NG

    REPLACE AIR FUEL RATIO SENSOR

    Click here

    OK

  2. CHECK TERMINAL VOLTAGE (+B OF AIR FUEL RATIO SENSOR)

    1. A150242C01

      *A

      Bank 1

      *B

      Bank 2

      *a

      Front view of wire harness connector

      (to Air Fuel Ratio Sensor)

      Disconnect the air fuel ratio sensor connector.

    2. Turn the engine switch on (IG).

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

      Standard Voltage

      Tester Connection

      Switch Condition

      Specified Condition

      C20-2 (+B) - Body ground

      Engine switch on (IG)

      11 to 14 V

      C19-2 (+B) - Body ground

      Engine switch on (IG)

      11 to 14 V

      Result

      Result

      OK

      NG
    NG

    INSPECT NO. 1 INTEGRATION RELAY (A/F)Click here

    OK

  3. 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

      Tester Connection

      Condition

      Specified Condition

      C20-1 (HA1A) - C31-17 (HA1A)

      Always

      Below 1 Ω

      C19-1 (HA2A) - C31-19 (HA2A)

      Always

      Below 1 Ω

      C20-1 (HA1A) or C31-17 (HA1A) - Body ground

      Always

      10 kΩ or higher

      C19-1 (HA2A) or C31-19 (HA2A) - Body ground

      Always

      10 kΩ or higher

      Result

      Result

      OK

      NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK WHETHER DTC OUTPUT RECURS

    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the tester on.

    4. Clear DTCs.

      Click here

      Powertrain > Engine and ECT > Clear DTCs

    5. Start the engine.

    6. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

    7. Read the output pending DTCs using the intelligent tester.

      Powertrain > Engine and ECT > Trouble Codes

      Result

      Result

      Proceed to

      No pending DTC is output

      A

      Pending DTC P0031, P0032, P0051, P0052, P101D or P103D is output

      B
    A

    CHECK FOR INTERMITTENT PROBLEMS

    Click here

    B

    REPLACE ECM

    Click here

  5. INSPECT NO. 1 INTEGRATION RELAY (A/F)

    1. Inspect the No. 1 integration relay (A/F).

      Click here

      Result

      Result

      OK

      NG
    NG

    REPLACE NO. 1 INTEGRATION RELAY (A/F)

    Click here

    OK

  6. CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY - AIR FUEL RATIO SENSOR AND BODY GROUND)

    1. Disconnect the air fuel ratio sensor connector.

    2. Remove the No. 1 integration relay from the engine room relay block.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      C20-2 (+B) - 1B-8

      Always

      Below 1 Ω

      C19-2 (+B) - 1B-8

      Always

      Below 1 Ω

      1B-7 - Body ground

      Always

      Below 1 Ω

      C20-2 (+B) or 1B-8 - Body ground

      Always

      10 kΩ or higher

      C19-2 (+B) or 1B-8 - Body ground

      Always

      10 kΩ or higher

      Result

      Result

      OK

      NG
    OK

    CHECK ECM POWER SOURCE CIRCUIT

    Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR