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. Although the DTC titles say oxygen sensor, these DTCs relate to the air fuel ratio sensor.
  2. Sensor 1 refers to the sensor mounted in front of the three-way catalytic converter and located near the engine assembly.
  3. When either of these DTCs is set, the ECM enters fail-safe mode. The ECM turns off the A/F sensor heater in fail-safe mode. Fail-safe mode continues until the ignition switch is turned off.

  4. The ECM provides a pulse width modulated signal to the 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.


    A200919E01


DTC No.
DTC Detection Condition
Trouble Area
P0031
Air fuel ratio sensor heater current less than 0.8 A
(1-trip detection logic)
  1. Open in air fuel ratio sensor heater circuit
  2. Air fuel ratio sensor (sensor 1)
  3. Integration relay (EFI relay)
  4. ECM
P0032
Air fuel ratio sensor heater current more than 10 A
(1-trip detection logic)
  1. Short in air fuel ratio sensor heater circuit
  2. Air fuel ratio sensor (sensor 1)
  3. Integration relay (EFI relay)
  4. ECM

WIRING DIAGRAM

Refer to DTC P2195 (Click here).

INSPECTION PROCEDURE

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

HINT:
Read freeze frame data using an 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 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.

1.INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)


    A085152E92

  1. Disconnect the air fuel ratio sensor connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    1 (HA1A) - 2 (+B)
    		20°C (68°F)
    		1.8 to 3.4 Ω
    1 (HA1A) - 4 (A1A-)
    		Always
    		10 kΩ or higher

    Text in Illustration 
    *1
    		Component without harness connected:
    (Air Fuel Ratio Sensor)

  1. Reconnect the air fuel ratio sensor connector.



NG
REPLACE AIR FUEL RATIO SENSOR (Click here)
OK


2.CHECK TERMINAL VOLTAGE (POWER SOURCE)


    A079114E19

  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
    B34-2 (+B) - Body ground
    		Ignition switch ON
    		11 to 14 V

    Text in Illustration 
    *1
    		Front view of wire harness connector:
    (to Air Fuel Ratio Sensor)

  1. Reconnect the air fuel ratio sensor connector.



NG
Go to step 4
OK


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


    A112605E16

  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
    B34-1 (HA1A) - B8-104 (HA1A)
    		Always
    		Below 1 Ω

    Standard Resistance (Check for Short):
    Tester Connection
    		Condition
    		Specified Condition
    B34-1 (HA1A) or B8-104 (HA1A) - Body ground
    		Always
    		10 kΩ or higher

    Text in Illustration 
    *1
    		Front view of wire harness connector:
    (to Air Fuel Ratio Sensor)
    *2
    		Front view of wire harness connector:
    (to ECM)

  1. Reconnect the air fuel ratio sensor connector.

  1. Reconnect the ECM connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM (Click here)  

4.CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR - INTEGRATION RELAY)


    A201271E01

  1. Disconnect the air fuel ratio sensor connector.

  1. Remove the integration relay (EFI relay) from the engine room relay block.

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

    Standard Resistance (Check for Open):
    Tester Connection
    		Condition
    		Specified Condition
    B34-2 (+B) - 1E-1
    		Always
    		Below 1 Ω

    Standard Resistance (Check for Short):
    Tester Connection
    		Condition
    		Specified Condition
    B34-2 (+B) or 1E-1 - Body ground
    		Always
    		10 kΩ or higher

    Text in Illustration 
    *1
    		Front view of wire harness connector:
    (to Air Fuel Ratio Sensor)
    *2
    		Front view of wire harness connector:
    (to Integration Relay)

  1. Reconnect the air fuel ratio sensor connector.

  1. Reinstall the integration relay.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPAIR OR REPLACE ECM POWER SOURCE CIRCUIT (Click here)