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

Engine Hybrid System. Corolla. Zre142 Aze141
2Az-Fe Engine Control. Corolla. Zre142 Aze141

DESCRIPTION

MONITOR DESCRIPTION

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING RANGE

CONFIRMATION DRIVING PATTERN

WIRING DIAGRAM

INSPECTION PROCEDURE

INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)

CHECK TERMINAL VOLTAGE (POWER SOURCE)

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

CHECK WHETHER DTC OUTPUT RECURS (DTC P0031 OR P0032)

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)


DESCRIPTION

Refer to DTC P2195 (Link).
HINT:
  1. When either 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. Fail-safe mode continues until the ignition switch is turned off.
  2. Although the DTC titles say the oxygen sensor, these DTCs relate to the air fuel ratio sensor.

  3. 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.


    Corolla. Zre142 Aze141.2Az-Fe Engine Control.Sfi System. Dtc P0031 Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 1 Sensor 1)


DTC No.
DTC Detection Condition
Trouble Area
P0031
Air fuel ratio sensor heater current is less than 0.8 A, even when the air fuel ratio sensor heater duty cycle is 50% or higher (1 trip detection logic).
  1. Open in air fuel ratio sensor heater circuit
  2. Air fuel ratio sensor (sensor 1)
  3. ECM
P0032
Air fuel ratio sensor heater current reaches the high limit
(Hybrid IC high current limiter monitor input "Fail") (1 trip detection logic).
  1. Short in air fuel ratio sensor heater circuit
  2. Air fuel ratio sensor (sensor 1)
  3. 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 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


Related DTCs
P0031: Air fuel ratio sensor (sensor 1) heater current (Low current)
P0032: Air fuel ratio sensor (sensor 1) heater current (High current)
Required Sensors/Components (Main)
Air fuel ratio sensor heater
Required Sensors/Components (Related)
-
Frequency of Operation
Continuous
Duration
10 seconds
MIL Operation
Immediate
Sequence of Operation
None

TYPICAL ENABLING CONDITIONS


All
Monitor runs whenever following DTCs are not present
None

P0031
Battery voltage
10.5 V or more
Air fuel ratio sensor heater output duty
50% or more
Time after engine start
10 seconds or more

P0032
Battery voltage
Less than 20 V
Time after engine start
10 seconds or more

TYPICAL MALFUNCTION THRESHOLDS


P0031
Air fuel ratio sensor heater current
Less than 0.8 A

P0032
Hybrid IC high current limiter monitor input
Fail

COMPONENT OPERATING RANGE


P0031:
Air fuel ratio sensor heater current
0.8 A or more

P0032:
Hybrid IC high current limiter monitor input
Pass

CONFIRMATION DRIVING PATTERN


Corolla. Zre142 Aze141.2Az-Fe Engine Control.Sfi System. Dtc P0031 Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 1 Sensor 1)

  1. Connect the Techstream to the DLC3.
  2. Turn the ignition switch to ON and turn the Techstream on.
  3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
  4. Turn the ignition switch off and wait for at least 30 seconds.
  5. Turn the ignition switch to ON and turn the Techstream 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 / Trouble Codes [E].
  10. Read the pending DTCs.
    HINT:
    1. If a pending DTC is output, the system is malfunctioning.
    2. 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 or P0032.
  13. Check the DTC judgment result.

    Techstream 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
    N/A
    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 N/A, perform steps [B] through [E] again.
  14. If no pending DTC is output, perform a universal trip and check for permanent DTCs (COROLLA_ZRE142 RM000000PDK0ZBX.html).
    HINT:
    1. If a permanent DTC is output, the system is malfunctioning.
    2. If no permanent DTC is output, the system is normal.

WIRING DIAGRAM

Refer to DTC P2195 (COROLLA_ZRE142 RM000000WC40PDX_07.html).

INSPECTION PROCEDURE

NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
HINT:
  1. Read freeze frame data using the Techstream. 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.
  2. Sensor 1 refers to the sensor closest to the engine assembly.
  3. Sensor 2 refers to the sensor farthest away from the engine assembly.
  4. 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 (COROLLA_ZRE142 RM000000WBY0H0X_10.html). 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 (COROLLA_ZRE142 RM0000033D600IX.html).



NG
REPLACE AIR FUEL RATIO SENSOR (COROLLA_ZRE142 RM0000033D700IX.html)
OK


2.CHECK TERMINAL VOLTAGE (POWER SOURCE)
Corolla. Zre142 Aze141.2Az-Fe Engine Control.Sfi System. Dtc P0031 Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 1 Sensor 1)

  1. Disconnect the air fuel ratio sensor connector.

  1. Turn the ignition switch to ON.

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

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    B92-2 (+B) - Body ground
    		Ignition switch ON
    		11 to 14 V

  1. Reconnect the air fuel ratio sensor connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (AIR FUEL RATIO SENSOR - ENGINE ROOM RELAY BLOCK)
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 (Check for Open):

    Tester Connection
    		Condition
    		Specified Condition
    B92-1 (HA1A) - B31-109 (HA1A)
    		Always
    		Below 1 Ω

    Standard Resistance (Check for Short):

    Tester Connection
    		Condition
    		Specified Condition
    B92-1 (HA1A) or B31-109 (HA1A) - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the air fuel ratio sensor connector.

  1. Reconnect the ECM connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (AIR FUEL RATIO SENSOR - ECM)
OK


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

  1. Connect the Techstream to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the Techstream on.

  1. Clear the DTCs (COROLLA_ZRE142 RM000000PDK0ZBX.html).

  1. Start the engine.

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

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

  1. Read DTCs.


Result:

Result
Proceed to
No output
A
P0031 or P0032
B


B
REPLACE ECM (COROLLA_ZRE142 RM000002WT402ZX.html)
A

CHECK FOR INTERMITTENT PROBLEMS (COROLLA_ZRE142 RM000000PDQ0VNX.html)