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

DESCRIPTION

MONITOR DESCRIPTION

CONFIRMATION DRIVING PATTERN

WIRING DIAGRAM

INSPECTION PROCEDURE

INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)

CHECK TERMINAL VOLTAGE (+B OF HEATED OXYGEN SENSOR)

CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - ECM)

CHECK WHETHER DTC OUTPUT RECURS

CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - NO. 1 INTEGRATION RELAY)

DESCRIPTION

HINT:

1. When any of these DTCs are stored, the ECM enters fail-safe mode. The ECM turns off the heated oxygen sensor heater in fail-safe mode. Fail-safe mode continues until the ignition switch is turned off.
   


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

MONITOR DESCRIPTION

1. 
   
   1. The ECM monitors the current applied to the heated oxygen sensor heater to check the heater for malfunctions. If the current is below the threshold value, the ECM will determine that there is an open circuit in the heater. If the current is above the threshold value, the ECM will determine that there is a short circuit in the heater.
      
   1. Example:
      
   1. The ECM stores DTC P0038 or P0058 when the current in the heated oxygen sensor heater is higher than 2 A. Conversely, when the heater current is below 0.3 A, DTC P0037 or P0057 is stored.
      

CONFIRMATION DRIVING PATTERN

1. Connect the intelligent tester to the DLC3.
   
2. Turn the ignition switch to ON and turn the tester on.
   
3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC operation).
   
4. Turn the ignition switch off and wait for at least 30 seconds.
   
5. Turn the ignition switch to ON and turn the tester 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 / DTC [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: P0037, P0038, P0057 or P0058.
    
13. Check the DTC judgment result.
    
    

    Tester Display	Description
    NORMAL	DTC judgment completed System normal
    ABNORMAL	DTC judgment completed System abnormal
    INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions
    N/A	Unable to perform DTC judgment 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.
       

WIRING DIAGRAM

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 intelligent tester. 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.
   
2. Bank 1 refers to the bank that includes No. 1 cylinder*.
   *: The No. 1 cylinder is the cylinder which is farthest from the transmission.
   
3. Bank 2 refers to the bank that does not include No. 1 cylinder.
   
4. Sensor 1 refers to the sensor closest to the engine assembly.
   
5. Sensor 2 refers to the sensor farthest away from the engine assembly.
   

1. Inspect the heated oxygen sensor (HILUX_TGN26 RM000002RV601FX.html).
   

1. Disconnect the heated oxygen sensor connectors.
   

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

   Standard Voltage:

   Tester Connection	Switch Condition	Specified Condition
   C88-2 (+B) - Body ground	Ignition switch ON	11 to 14 V
   C152-2 (+B) - Body ground	Ignition switch ON	11 to 14 V

   Text in Illustration

   *A	for Bank 1
   *B	for Bank 2
   *a	Front view of wire harness connector (to Heated Oxygen Sensor)

1. Disconnect the heated oxygen sensor connectors.
   

2. Disconnect the ECM connector.
   

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

   Standard Resistance:

   
   

   Tester Connection	Condition	Specified Condition
   C88-1 (HT1B) - C129-1 (HT1B)	Always	Below 1 Ω
   C152-1 (HT2B) - C130-5 (HT2B)	Always	Below 1 Ω
   C88-1 (HT1B) or C129-1 (HT1B) - Body ground	Always	10 kΩ or higher
   C152-1 (HT2B) or C130-5 (HT2B) - Body ground	Always	10 kΩ or higher

1. Connect the intelligent tester to the DLC3.
   

2. Turn the ignition switch to ON and turn the tester on.
   

3. Clear the DTCs (HILUX_TGN26 RM000000PDK12JX.html).
   

4. Turn the ignition switch off and wait for at least 30 seconds.
   

5. Start the engine.
   

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

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

8. Read the pending DTCs.
   

1. Disconnect the heated oxygen sensor connectors.
   

2. Remove the No. 1 integration relay from the engine room relay block and junction block assembly.
   

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

   Standard Resistance:

   
   

   Tester Connection	Condition	Specified Condition
   C88-2 (+B) - 1J-5	Always	Below 1 Ω
   C152-2 (+B) - 1J-5	Always	Below 1 Ω
   C88-2 (+B) or 1J-5 - Body ground	Always	10 kΩ or higher
   C152-2 (+B) or 1J-5 - Body ground	Always	10 kΩ or higher