SFI SYSTEM, Diagnostic DTC:P0134, P0154

DTC Code DTC Name
P0134 Oxygen Sensor Circuit No Activity Detected (Bank 1 Sensor 1)
P0154 Oxygen Sensor Circuit No Activity Detected (Bank 2 Sensor 1)

DESCRIPTION

The heated oxygen sensor is used to monitor oxygen concentration in the exhaust gas. For optimum catalytic converter operation, the air-fuel mixture must be maintained near the ideal stoichiometric air-fuel ratio. The heated oxygen sensor output voltage changes suddenly in the vicinity of the stoichiometric air-fuel ratio. The ECM adjusts the fuel injection time so that the air-fuel ratio is nearly stoichiometric. The heated oxygen sensor generates a voltage between 0.1 and 0.9 V in response to the oxygen concentration in the exhaust gas.

If the oxygen concentration in the exhaust gas increases, the air-fuel ratio is called LEAN. The heated oxygen sensor voltage drops below 0.45 V, which informs the ECM of the LEAN condition.

If oxygen is not in the exhaust gas, the air-fuel ratio is called RICH. The heated oxygen sensor voltage increases above 0.45 V, which informs the ECM of the RICH condition.

A01GMH6E04

Tech Tips

The ECM provides a pulse width modulated control circuit to adjust current through the heater. The heated oxygen sensor heater circuit uses a relay on the +B side of the circuit.

A01GIATE05
DTC No. DTC Detection Condition Trouble Area

P0134

P0154


  • After engine is warmed up, heated oxygen sensor (sensor 1) does not indicate RICH (greater than 0.45 V) even once when conditions (a), (b), (c), (d) and (e) continue for 65 seconds (1 trip detection logic):


    • (a) Engine speed: 1400 rpm or more

    • (b) Vehicle speed: 40 km/h (25 mph) or more

    • (c) Throttle valve is not fully closed

    • (d) 120 seconds or more after starting engine

    • (e) ECT is more than 40°C (104°F)


  • Open or short in heated oxygen sensor (sensor) circuit

  • Heated oxygen sensor (sensor 1)

  • Ventilation valve and hose

  • Air induction system

  • Fuel pressure

  • Injector

  • Gas leakage in exhaust system

  • A/F relay

  • ECM

Tech Tips

Confirm the heated oxygen sensor (sensor 1) voltage. Enter the following menus: Powertrain / Engine / Data List / Primary / O2S B1S1 (or O2S B2S1).

If the voltage is less than 0.1 V, the sensor circuit may be open or short.

MONITOR DESCRIPTION

The ECM uses the heated oxygen sensor to optimize the air-fuel mixture with closed-loop fuel control. This control helps decrease exhaust emissions by providing the catalyst with a nearly stoichiometric mixture. The sensor detects the oxygen level in the exhaust gas and the ECM uses this data to control the air-fuel ratio. The sensor output voltage range is from 0.1 V to 0.9 V. If the signal voltage is less than 0.45 V, the air-fuel ratio is LEAN. If the signal voltage is more than 0.45 V, the air-fuel ratio is RICH. If the sensor does not indicate RICH at least once despite the conditions for the closed-loop fuel control being met and the specified time period has passed, the ECM will conclude that the closed-loop fuel control is malfunctioning. The ECM will illuminate the MIL and a DTC is set.

WIRING DIAGRAM

A01GIYME03

CONFIRMATION DRIVING PATTERN

A01GJQ2E03

  1. Connect the intelligent tester to the DLC3.

  2. Allow the engine to idle until ECT reaches 40°C (104°F).

  3. Allow the vehicle to run at 60 km/h (38 mph) or more for 3 minutes or more.

INSPECTION PROCEDURE

Tech Tips

It is possible the malfunctioning area can be found using the Active Test Control operation. The Active Test can determine if the heated oxygen sensor or other potential trouble areas are malfunctioning or not.

The injection volume can be switched to -12.5% (decrease) or +24.8% (increase) by the Active Test.

The Active Test procedure enables a technician to check and graph the output voltage of the heated oxygen sensors.


Tech Tips


  • The Control the Injection Volume operation lowers the fuel injection volume by 12.5% or increases the injection volume by 24.8%.

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

Tester Display Injection Volume Status Voltage
O2S B1S1 or O2S B2S1 +24.8% Rich More than 0.55 V
O2S B1S1 or O2S B2S1 -12.5% Lean Less than 0.4 V
O2S B1S2 or O2S B2S2 +24.8% Rich More than 0.5 V
O2S B1S2 or O2S B2S2 -12.5% Lean Less than 0.4 V

Note

The heated oxygen sensor (sensor 1) output has a few seconds of delay and the heated oxygen sensor (sensor 2) output has a maximum of 20 seconds of delay.

If the vehicle is short on fuel, the air-fuel ratio becomes LEAN and the DTCs will be recorded.

Case Front HO2 Sensor (Sensor 1) Output Voltage Rear HO2 Sensor (Sensor 2) Output Voltage Main Suspected Trouble Area
1 A01GHX3E16 A01GJQ7E01 A01GHX3E16 A01GKFWE02 -
2 A01GHX3E16 A01GJHVE01 A01GHX3E16 A01GKFWE02
  • Front HO2 sensor

  • Front HO2 sensor heater

  • Front HO2 sensor circuit

3 A01GHX3E16 A01GJQ7E01 A01GHX3E16 A01GJHVE01
  • Rear HO2 sensor

  • Rear HO2 sensor heater

  • Rear HO2 sensor circuit

4 A01GHX3E16 A01GJHVE01 A01GHX3E16 A01GJHVE01
  • 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 conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, 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.

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

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

  • No. 1 cylinder is located in the front part of the engine, opposite the transmission.

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

PROCEDURE


  1. CHECK OTHER DTC OUTPUT


    1. Connect the intelligent tester to the DLC3.

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

    3. Read the DTCs.

      Result
      Display (DTC output) Proceed to
      P0134 or P0154 A
      P0134 or P0154 and other DTCs B

    B
    A
  2. READ DATA LIST (HEATED OXYGEN SENSOR (SENSOR 1) VOLTAGE)


    1. Connect the intelligent tester to the DLC3.

    2. Enter the following menus: Powertrain / Engine / Data List / Primary / O2S B1S1 (or O2S B2S1).

    3. Allow the engine to idle until the ECT reaches 40°C (104°F).

    4. Quickly depress the accelerator pedal 3 times until the engine RPM reaches 4000 rpm. Then, read the heated oxygen sensor (sensor 1) voltage.

      Standard voltage
      The heated oxygen sensor (sensor 1) voltage is 0.45 V or more at least once.

    OK
    NG
  3. CHECK CONNECTION VENTILATION HOSE

    OK
    Ventilation hose is connected correctly and is not damaged.

    NG
    OK
  4. INSPECT HEATED OXYGEN SENSOR

    A01GJX6E02

    1. Disconnect the E56 and E57 sensor connectors.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      1 (HT1A) - 2 (+B) Always 11 to 16 Ω
      1 (HT2A) - 2 (+B) Always 11 to 16 Ω
      1 (HT1A) - 4 (E2) Always 10 kΩ or higher
      1 (HT2A) - 4 (E2) Always 10 kΩ or higher

    NG
    OK
  5. INSPECT ENGINE ROOM NO. 2 JUNCTION BLOCK (A/F RELAY)

    A01GKYIE01

    1. Remove the terminal cover.

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

      Standard voltage
      Tester Connection Switch Condition Specified Condition
      +B - Body ground Always 11 to 14 V
      A/F - Body ground Engine switch on (IG) 11 to 14 V

    NG
    OK
  6. CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR (SENSOR 1) - ECM)

    A01GN9GE01

    1. Disconnect the E56 and E57 sensor connectors.

    2. Disconnect the E1 and E3 ECM connectors.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      E56-1 (HT1A) - E3-3 (HT1A) Always Below 1 Ω
      E56-3 (OX1A) - E3-28 (OX1A) Always Below 1 Ω
      E57-1 (HT2A) - E3-2 (HT2A) Always Below 1 Ω
      E57-3 (OX2A) - E3-27 (OX2A) Always Below 1 Ω
      E56-4 (E2) - E1-28 (E2) Always Below 1 Ω
      E57-4 (E2) - E1-28 (E2) Always Below 1 Ω
      E56-1 (HT1A) or E3-3 (HT1A) - Body ground Always 10 kΩ or higher
      E56-3 (OX1A) or E3-28 (OX1A) - Body ground Always 10 kΩ or higher
      E57-1 (HT2A) or E3-2 (HT2A) - Body ground Always 10 kΩ or higher
      E57-3 (OX2A) or E3-27 (OX2A) - Body ground Always 10 kΩ or higher

    NG
    OK
  7. CHECK AIR INDUCTION SYSTEM


    1. Check the air induction system for vacuum leaks.

      OK
      There are no vacuum leaks in air induction system.

    NG
    OK
  8. CHECK FUEL PRESSURE


    1. Check the fuel pressure Click here.


    NG
    OK
  9. INSPECT FUEL INJECTOR


    1. Check the injector injection [whether fuel volume is high or low, and whether injection pattern is poor] Click here.


    NG
    OK
  10. CHECK FOR EXHAUST GAS LEAKAGE

    OK
    No gas leakage.

    NG
    OK
  11. PERFORM CONFIRMATION DRIVING PATTERN

    Tech Tips

    Clear all DTCs before performing the confirmation driving pattern.


    NEXT
  12. READ OUTPUT DTC (DTC P0134 OR P0154 IS OUTPUT AGAIN)


    1. Start the engine and allow the engine to idle for 15 seconds or more.

    2. Read the DTC.

      Result
      Display (DTC output) Proceed to
      None A
      P0134 or P0154 B

    B
    A
  13. CONFIRM IF VEHICLE HAS RUN OUT OF FUEL


    1. If the vehicle has run out of fuel, proceed to A.

    2. If the vehicle has not run out of fuel, proceed to B.


    B
    A