DTC P0031 P0032 P101D 2ZR-FXE

DTC P0031 Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 1 Sensor 1)

DTC P0032 Oxygen (A/F) Sensor Heater Control Circuit High (Bank 1 Sensor 1)

DTC P101D A/F Sensor Heater Circuit Performance Bank 1 Sensor 1 Stuck ON

  1. Description

  2. Monitor description

  3. Monitor strategy

  4. Typical enabling conditions

  5. Confirmation driving pattern

  6. Wiring diagram

  7. Inspection procedure

  8. Inspect air fuel ratio sensor (heater resistance)

  9. Check terminal voltage (+b of air fuel ratio sensor)

  10. Check harness and connector (air fuel ratio sensor - ecm)

  11. Check whether dtc output recurs (dtc p0031, p0032 or p101d)

Description

Refer to DTC P2195.

HINT:

  1. When either of these DTCs is set, the ECM enters fail-safe mode. The ECM turns off the air fuel ratio sensor heater in fail-safe mode. Fail-safe mode continues until the power switch is turned off.
  2. Although the DTC titles say the oxygen sensor, these DTCs relate to the air fuel ratio sensor.
  3. Sensor 1 refers to the sensor mounted in front of the Three-way catalytic converter and located near the engine assembly.
  4. The ECM uses pulse width modulation to adjust the current through the heater. The air fuel ratio sensor heater circuit uses a relay on the +B side of the circuit.
    Lexus DTC P0031 DTC P0032 DTC P101D Description
DTC No. DTC Detection Condition Trouble Area
P0031 Air fuel ratio sensor heater current is below 0.8 A, even when the air fuel ratio sensor heater duty cycle is 10% or more (1 trip detection logic).
  1. Open in air fuel ratio sensor (sensor 1) heater circuit
  2. Air fuel ratio sensor heater (sensor 1)
  3. ECM
P0032 An air fuel ratio sensor heater current reaches the high limit (Hybrid IC high current limiter port "Fail") (1 trip detection logic).
  1. Short in air fuel ratio sensor (sensor 1) heater circuit
  2. Air fuel ratio sensor heater (sensor 1)
  3. ECM
P101D The heater current is higher than the specified value while the heater is not operating (1 trip detection logic). ECM

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 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 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 sets a DTC.

Monitor strategy

Frequency of Operation Continuous
Duration 10 seconds: P0031
10.24 seconds: P0032
1 second: P101D
MIL Operation Immediately
Sequence of Operation None

Typical enabling conditions

P0031:
Air fuel ratio sensor heater duty cycle 10% or more
P0032:
Air fuel ratio sensor heater duty cycle More than 0%
P101D:
Air fuel ratio sensor heater duty cycle 10 to 60%
Air fuel ratio sensor heater ON current 0.8 A or higher

Confirmation driving pattern

Lexus DTC P0031 DTC P0032 DTC P101D Confirmation driving pattern
  1. Connect the intelligent tester to the DLC3.
  2. Turn the power switch on (IG) and turn the tester on.
  3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC operation).
  4. Turn the power switch off and wait for 30 seconds.
  5. Turn the power switch on (IG) and turn the tester on [A].
  6. Put the engine in inspection mode (maintenance mode) .
  7. Start the engine and idle it for 5 minutes or more [B].
  8. With the vehicle stationary, depress the accelerator pedal and maintain an engine speed of 2500 rpm for 1 minute [C].
  9. Idle the engine for 5 minutes or more [D].
  10. Enter the following menus: Powertrain / Engine and ECT / DTC.
  11. Read the DTC [E].

    HINT:

    1. If a DTC is output, the system is malfunctioning.
    2. If a DTC is not output, perform the following procedure.
  12. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
  13. Input the DTC: P0031, P0032 or P101D.
  14. Check the DTC judgment result.
    Tester Display Description
    NORMAL
    1. DTC judgment completed
    2. System normal
    ABNORMAL
    1. DTC judgment completed
    2. System abnormal
    INCOMPLETE
    1. DTC judgment not completed
    2. Perform driving pattern after confirming DTC enabling conditions
    UNKNOWN
    1. Unable to perform DTC judgment
    2. Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

    HINT:

    1. If the judgment result shows NORMAL, the system is normal.
    2. If the judgment result shows ABNORMAL, the system has a malfunction.
    3. If the judgment result shows INCOMPLETE or UNKNOWN, perform steps [B] through [E] again.

Wiring diagram

Refer to DTC P2195.

Inspection procedure

NOTICE:

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

HINT:

  1. Refer to "Data List / Active Test" [A/F Heater Duty #1] .
  2. Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
  3. Sensor 1 refers to the sensor closest to the engine assembly.
  4. Sensor 2 refers to the sensor farthest away from the engine assembly.
  5. Change the fuel injection volume using the Control the Injection Volume function provided in the Active Test and monitor the air fuel ratio sensor output voltage. If the sensor output voltage does not change (almost no reaction) while performing the Active Test, the sensor may be malfunctioning.

1.INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)

  1. Inspect the air fuel ratio sensor .

  NG  
REPLACE AIR FUEL RATIO SENSOR
 
OK  
   


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

Lexus DTC P0031 DTC P0032 DTC P101D Disconnect the air fuel ratio sensor connector.

  1. Disconnect the air fuel ratio sensor connector.

  1. Turn the power switch on (IG).

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

    Standard Voltage:

    Tester Connection Switch Condition Specified Condition
    D23-2 (+B) - Body ground Power switch on (IG) 11 to 14 V
    Text in Illustration
    *a Front view of wire harness connector
    (to Air Fuel Ratio Sensor (Sensor 1))
  NG  
REPAIR OR REPLACE HARNESS OR CONNECTOR (AIR FUEL RATIO SENSOR - EFI MAIN RELAY)
 
OK  
   


3.CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR - ECM)

  1. Disconnect the air fuel ratio sensor connector.

  1. Disconnect the ECM connector.

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

    Standard Resistance:

    Tester Connection Condition Specified Condition
    D23-1 (HA1A) - D27-18 (HA1A) Always Below 1 ?
    D23-1 (HA1A) or D27-18 (HA1A) - Body ground Always 10 k? or higher
  NG  
REPAIR OR REPLACE HARNESS OR CONNECTOR
 
OK  
   


4.CHECK WHETHER DTC OUTPUT RECURS (DTC P0031, P0032 OR P101D)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the tester on.

  1. Clear the DTCs .

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

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

  1. Read the DTCs.

    Result
    Result Proceed to
    DTC is not output A
    DTC P0031, P0032 or P101D is output B
  B  
REPLACE ECM
 
A  
   
CHECK FOR INTERMITTENT PROBLEMS