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)

for Preparation Click here


DESCRIPTION

Refer to DTC P2195 (Click here).

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 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.


    A157557E23


DTC No.
DTC Detection Condition
Trouble Area
P0031
Air fuel ratio sensor heater current less than 0.8 A, even when the air fuel ratio sensor heater duty cycle is 30% or more
(1 trip detection logic)
  1. Open in air fuel ratio sensor (sensor 1) heater circuit
  2. Air fuel ratio sensor (sensor 1) heater
  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 (sensor 1) heater circuit
  2. Air fuel ratio sensor (sensor 1) heater
  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 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


Related DTCs
P0031: Air fuel ratio sensor heater range check (Low current)
P0032: Air fuel ratio sensor heater range check (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 not present
None

P0031 
Battery voltage
10.5 V or more
Time after engine start
10 seconds or more
Heater output duty cycle
30% or more

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

TYPICAL MALFUNCTION THRESHOLDS


P0031 
Heater current
Less than 0.8 A

P0032 
Hybrid IC high current limiter monitor input
Fail

COMPONENT OPERATING RANGE


P0031 
Heater current
0.8 A or more

P0032 
Hybrid IC high current limiter monitor input
Pass

CONFIRMATION DRIVING PATTERN


A198819E21

  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 operation) (Click here).
  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.
  14. If the judgment result shows INCOMPLETE or N/A, perform steps [B] through [E] again.
  15. If no pending DTC is output, perform a universal trip and check for permanent DTCs (Click here).

    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 (Click here).

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. 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 (Click here). If the sensor output voltage does not change (almost no reaction) while performing the Active Test, the sensor may be malfunctioning.
  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.
1.INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)

  1. Inspect the air fuel ratio sensor (Click here).



NG
REPLACE AIR FUEL RATIO SENSOR (Click here)
OK


2.CHECK TERMINAL VOLTAGE (POWER SOURCE)


    A170690E03

  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
    		Switch Condition
    		Specified Condition
    B89-2 (+B) - Body ground
    		Ignition switch ON
    		11 to 14 V

  1. Reconnect the air fuel ratio sensor connector.



NG
Go to step 5
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
    B89-1 (HA1A) - B31-104 (HA1A)
    		Always
    		Below 1 Ω

    Standard Resistance (Check for Short):

    Tester Connection
    		Condition
    		Specified Condition
    B89-1 (HA1A) or B31-104 (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 DTCs (Click here).

  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 the DTCs.

    Result:

    Result
    		Proceed to
    DTC is not output
    		A
    DTC P0031 or P0032 is output
    		B


B
REPLACE ECM (Click here)
A

CHECK FOR INTERMITTENT PROBLEMS (Click here)  

5.INSPECT FUSE (EFI NO. 2 FUSE)


    A157412E01

  1. Remove the EFI No. 2 fuse from the engine room relay block.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    EFI No. 2 fuse
    		Always
    		Below 1 Ω

  1. Reinstall the EFI No. 2 fuse.



NG
REPLACE FUSE (EFI NO. 2)
OK

REPAIR OR REPLACE HARNESS OR CONNECTOR (INTEGRATION RELAY (EFI MAIN RELAY) - AIR FUEL RATIO SENSOR)