Dtc P0037 Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2)

DESCRIPTION

MONITOR DESCRIPTION

WIRING DIAGRAM

CONFIRMATION DRIVING PATTERN

INSPECTION PROCEDURE

INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)

CHECK TERMINAL VOLTAGE (+B OF HO2 SENSOR)

INSPECT INTEGRATION RELAY (EFI)

CHECK HARNESS AND CONNECTOR (HO2 SENSOR - INTEGRATION RELAY)

CHECK HARNESS AND CONNECTOR (HO2 SENSOR - ECM)

CHECK WHETHER DTC OUTPUT RECURS

DESCRIPTION

1. Refer to DTC P0137 (Click here).
   

HINT:

1. When any of these DTCs is stored, the ECM enters fail-safe mode. The ECM turns off the Heated Oxygen (HO2) Sensor heater in fail-safe mode. Fail-safe mode continues until the engine switch is turned off.
   


2. The ECM provides a pulse width modulated control circuit to adjust the current through the heater. The HO2 sensor heater circuit uses a relay on the +B side of the circuit.
   
   
   
   
   
   

MONITOR DESCRIPTION

1. Heated oxygen sensor heater range check (P0037, P0038, P0057, P0058, P102D and P105D):
   The ECM monitors the current applied to the heated oxygen sensor heater to check the heater for malfunctions.
   If the heater current is outside the normal range, the signal transmitted by the heated oxygen sensor becomes inaccurate. When the current in the heated oxygen sensor heater is outside the normal operating range, the ECM interprets this as a malfunction in the sensor heater and stores a DTC.
   

WIRING DIAGRAM

CONFIRMATION DRIVING PATTERN

INSPECTION PROCEDURE

HINT:

1. Sensor 2 refers to the sensor mounted behind the Three-Way Catalytic Converter (TWC) and located far from the engine assembly.
   
2. Read freeze frame data using the GTS. Freeze frame data records the engine condition when malfunctions are detected. 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.
   
3. Bank 1 refers to the bank that includes the No. 1 cylinder*.
   *: The No. 1 cylinder is the cylinder which is farthest from the transmission.
   
4. Bank 2 refers to the bank that does not include the No. 1 cylinder.
   
5. Sensor 1 refers to the sensor closest to the engine assembly.
   
6. Sensor 2 refers to the sensor farthest away from the engine assembly.
   

1. Disconnect the C20 or C56 heated oxygen (HO2) sensor connector.
   

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

   Standard Resistance:

   Tester Connection	Condition	Specified Condition
   1 (HT1B) - 2 (+B)	20°C (68°F)	11 to 16 Ω
   1 (HT1B) - 4 (E1)	Always	10 kΩ or higher
   1 (HT2B) - 2 (+B)	20°C (68°F)	11 to 16 Ω
   1 (HT2B) - 4 (E1)	Always	10 kΩ or higher

1. Disconnect the C20 or C56 HO2 sensor connector.
   

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

   Standard Voltage:

   Tester Connection	Switch Condition	Specified Condition
   C20-2 (+B) - Body ground	Engine switch on (IG)	11 to 14 V
   C56-2 (+B) - Body ground	Engine switch on (IG)	11 to 14 V

   Result

   Result	Proceed to
   NG	A
   OK	B

1. Remove the integration relay from the engine room relay block.
   

2. Inspect the EFI MAIN fuse.
   

   1. Remove the EFI MAIN fuse from the integration relay.
      

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

      Standard Resistance:

      
      

      Tester Connection	Condition	Specified Condition
      EFI MAIN fuse	Always	Below 1 Ω

   3. Reinstall the EFI MAIN fuse.
      

3. Inspect the EFI relay.
   

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

      Standard Resistance:

      Tester Connection	Condition	Specified Condition
      1C-1 - 1B-4	No battery voltage applied to terminals 1B-2 and 1B-3	10 kΩ or higher
      	Battery voltage applied to terminals 1B-2 and 1B-3	Below 1 Ω

1. Check the EFI NO. 2 fuse.
   

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

   2. 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

   3. Reinstall the EFI NO. 2 fuse.
      

2. Disconnect the C20 or C56 HO2 sensor connector.
   

3. Remove the integration relay from the engine room relay block.
   

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

   Standard Resistance:

   
   

   Tester Connection	Condition	Specified Condition
   C20-2 (+B) - 1B-4	Always	Below 1 Ω
   C56-2 (+B) - 1B-4	Always	Below 1 Ω
   C20-2 (+B) or 1B-4 - Body ground	Always	10 kΩ or higher
   C56-2 (+B) or 1B-4 - Body ground	Always	10 kΩ or higher

1. Disconnect the C20 or C56 HO2 sensor connector.
   

2. Disconnect the C45 ECM connector.
   

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

   Standard Resistance:

   
   

   Tester Connection	Condition	Specified Condition
   C20-1 (HT1B) - C45-45 (HT1B)	Always	Below 1 Ω
   C56-1 (HT2B) - C45-44 (HT2B)	Always	Below 1 Ω
   C20-1 (HT1B) or C45-45 (HT1B) - Body ground	Always	10 kΩ or higher
   C56-1 (HT2B) or C45-44 (HT2B) - Body ground	Always	10 kΩ or higher

1. Connect the GTS to the DLC3.
   

2. Turn the engine switch on (IG).
   

3. Turn the tester on.
   

4. Clear DTCs (Click here).
   

5. Start the engine.
   

6. Allow the engine to idle for 2 minutes or more.
   

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

8. Read DTCs.
   
   

   Result

   Result	Proceed to
   No DTC is output	A
   P0037, P0038, P0057, P0058, P102D and/or P105D are output	B